More Precise Index Status Data for Your Site Variations

Webmaster Level: Intermediate

The Google Webmaster Tools Index Status feature reports how many pages on your site are indexed by Google. In the past, we didn’t show index status data for HTTPS websites independently, but rather we included everything in the HTTP site’s report. In the last months, we’ve heard from you that you’d like to use Webmaster Tools to track your indexed URLs for sections of your website, including the parts that use HTTPS.

We’ve seen that nearly 10% of all URLs already use a secure connection to transfer data via HTTPS, and we hope to see more webmasters move their websites from HTTP to HTTPS in the future. We’re happy to announce a refinement in the way your site’s index status data is displayed in Webmaster Tools: the Index Status feature now tracks your site’s indexed URLs for each protocol (HTTP and HTTPS) as well as for verified subdirectories.

This makes it easy for you to monitor different sections of your site. For example, the following URLs each show their own data in Webmaster Tools Index Status report, provided they are verified separately:

HTTP	HTTPS
http://www.example.com/	https://www.example.com/
http://example.com	https://example.com
http://www.example.com/folder/	https://www.example.com/folder/
http://example.com/folder/	https://example.com/folder/

The refined data will be visible for webmasters whose site's URLs are on HTTPS or who have subdirectories verified, such as https://example.com/folder/. Data for subdirectories will be included in the higher-level verified sites on the same hostname and protocol.

If you have a website on HTTPS or if some of your content is indexed under different subdomains, you will see a change in the corresponding Index Status reports. The screenshots below illustrate the changes that you may see on your HTTP and HTTPS sites’ Index Status graphs for instance:

HTTP site’s Index Status showing drop

HTTPS site’s Index Status showing increase

An “Update” annotation has been added to the Index Status graph for March 9th, showing when we started collecting this data. This change does not affect the way we index your URLs, nor does it have an impact on the overall number of URLs indexed on your domain. It is a change that only affects the reporting of data in Webmaster Tools user interface.

In order to see your data correctly, you will need to verify all existing variants of your site (www., non-www., HTTPS, subdirectories, subdomains) in Google Webmaster Tools. We recommend that your preferred domains and canonical URLs are configured accordingly.

Note that if you wish to submit a Sitemap, you will need to do so for the preferred variant of your website, using the corresponding URLs. Robots.txt files are also read separately for each protocol and hostname.

We hope that you’ll find this update useful, and that it’ll help you monitor, identify and fix indexing problems with your website. You can find additional details in our Index Status Help Center article. As usual, if you have any questions, don’t hesitate to ask in our webmaster Help Forum.

Posted by Zineb Ait Bahajji, WTA, thanks to the Webmaster Tools team.

Introducing the new Webmaster Academy

Webmaster level: Beginner

Our Webmaster Academy is now available with new and targeted content!

Two years ago, Webmaster Academy launched to teach new and beginner webmasters how to make great websites. In addition to adding new content, we've now expanded and improved information on three important topics:

• Making a great site that’s valuable to your audience (Module 1)
• Learning how Google sees and understands your site (Module 2)
• Communicating with Google about your site (Module 3)

If you often find yourself overwhelmed by the depth or breadth of our resources, Webmaster Academy will help you understand the basics of creating a website and having it found in Google Search. If you’re an experienced webmaster, you might learn something new too.

Enjoy, learn, and share your feedback!

Posted by Mary Chen, Webmaster Outreach Team

App Engine IP Range Change Notice

Google uses a wide range of IP addresses for its different services, and the addresses may change without notification. Google App Engine is a Platform as a Service offering which hosts a wide variety of 3rd party applications. This post announces changes in the IP address range and headers used by the Google App Engine URLFetch (outbound HTTP) and outbound sockets APIs.

While we recommend that App Engine IP ranges not be used to filter inbound requests, we are aware that some services have created filters that rely on specific addresses. Google App Engine will be changing its IP range beginning this month. Please see these instructions to determine App Engine’s IP range.

Additionally, the HTTP User-Agent header string that historically allowed identification of individual App Engine applications should no longer be relied on to identify the application. With the introduction of outbound sockets for App Engine, applications may now make HTTP requests without using the URLFetch API, and those requests may set a User-Agent of their own choosing.

Posted by the Google App Engine Team

Musical artists: your official tour dates in the Knowledge Graph

Webmaster level: all

When music lovers search for their favorite band on Google, we often show them a Knowledge Graph panel with lots of information about the band, including the band’s upcoming concert schedule. It’s important to fans and artists alike that this schedule be accurate and complete. That’s why we’re trying a new approach to concert listings. In our new approach, all concert information for an artist comes directly from that artist’s official website when they add structured data markup.

If you’re the webmaster for a musical artist’s official website, you have several choices for how to participate:

1. You can implement schema.org markup on your site. That’s easier than ever, since we’re supporting the new JSON-LD format (alongside RDFa and microdata) for this feature.
2. Even easier, you can install an events widget that has structured data markup built in, such as Bandsintown, BandPage, ReverbNation, Songkick, or GigPress.
3. You can label the site’s events with your mouse using Google’s point-and-click webmaster tool: Data Highlighter.

All these options are explained in detail in our Help Center. If you have any questions, feel free to ask in our Webmaster Help forums. So don’t you worry `bout a schema.org/Thing ... just mark up your site’s events and let the good schema.org/Times roll!

Posted by Justin Boyan, Product Manager, Google Search

3 tips to find hacking on your site, and ways to prevent and fix it

Google shows this message in search results for sites that we believe may have been compromised.You might not think your site is a target for hackers, but it's surprisingly common. Hackers target large numbers of sites all over the web in order to exploit the sites' users or reputation.

One common way hackers take advantage of vulnerable sites is by adding spammy pages. These spammy pages are then used for various purposes, such as redirecting users to undesired or harmful destinations. For example, we’ve recently seen an increase in hacked sites redirecting users to fake online shopping sites.

Once you recognize that your website may have been hacked, it’s important to diagnose and fix the problem as soon as possible. We want webmasters to keep their sites secure in order to protect users from spammy or harmful content.

3 tips to help you find hacked content on your site

1. Check your site for suspicious URLs or directories
   Keep an eye out for any suspicious activity on your site by performing a “site:” search of your site in Google, such as [site:example.com]. Are there any suspicious URLs or directories that you do not recognize?
   
   You can also set up a Google Alert for your site. For example, if you set a Google Alert for [site:example.com (viagra|cialis|casino|payday loans)], you’ll receive an email when these keywords are detected on your site.
   
   
2. Look for unnatural queries on the Search Queries page in Webmaster Tools
   The Search Queries page shows Google Web Search queries that have returned URLs from your site. Look for unexpected queries as it can be an indication of hacked content on your site.
   
   Don’t be quick to dismiss queries in different languages. This may be the result of spammy pages in other languages placed on your website.
   
   
   

   

   Example of an English site hacked with Japanese content.

3. Enable email forwarding in Webmaster Tools
   Google will send you a message if we detect that your site may be compromised. Messages appear in Webmaster Tools’ Message Center but it's a best practice to also forward these messages to your email. Keep in mind that Google won’t be able to detect all kinds of hacked content, but we hope our notifications will help you catch things you may have missed.

Tips to fix and prevent hacking

• Stay informed
  The Security Issues section in Webmaster Tools will show you hacked pages that we detected on your site. We also provide detailed information to help you fix your hacked site. Make sure to read through this documentation so you can quickly and effectively fix your site.


• Protect your site from potential attacks
  It's better to prevent sites from being hacked than to clean up hacked content. Hackers will often take advantage of security vulnerabilities on commonly used website management software. Here are some tips to keep your site safe from hackers:


• Always keep the software that runs your website up-to-date.
• If your website management software tools offer security announcements, sign up to get the latest updates.
• If the software for your website is managed by your hosting provider, try to choose a provider that you can trust to maintain the security of your site.

We hope this post makes it easier for you to identify, fix, and prevent hacked spam on your site. If you have any questions, feel free to post in the comments, or drop by the Google Webmaster Help Forum.

If you find suspicious sites in Google search results, please report them using the Spam Report tool.

Posted by Megumi Hitomi, Japanese Search Quality Team

Infinite scroll search-friendly recommendations

Webmaster Level: Advanced

Your site’s news feed or pinboard might use infinite scroll—much to your users’ delight! When it comes to delighting Googlebot, however, that can be another story. With infinite scroll, crawlers cannot always emulate manual user behavior--like scrolling or clicking a button to load more items--so they don't always access all individual items in the feed or gallery. If crawlers can’t access your content, it’s unlikely to surface in search results.

To make sure that search engines can crawl individual items linked from an infinite scroll page, make sure that you or your content management system produces a paginated series (component pages) to go along with your infinite scroll.

Infinite scroll page is made “search-friendly” when converted to a paginated series -- each component page has a similar <title> with rel=next/prev values declared in the <head>.

You can see this type of behavior in action in the infinite scroll with pagination demo created by Webmaster Trends Analyst, John Mueller. The demo illustrates some key search-engine friendly points:

• Coverage: All individual items are accessible. With traditional infinite scroll, individual items displayed after the initial page load aren’t discoverable to crawlers.
• No overlap: Each item is listed only once in the paginated series (i.e., no duplication of items).

Search-friendly recommendations for infinite scroll

1. Before you start:
   • Chunk your infinite-scroll page content into component pages that can be accessed when JavaScript is disabled.
   • Determine how much content to include on each page.
     • Be sure that if a searcher came directly to this page, they could easily find the exact item they wanted (e.g., without lots of scrolling before locating the desired content).
     • Maintain reasonable page load time.
   • Divide content so that there’s no overlap between component pages in the series (with the exception of buffering).



The example on the left is search-friendly, the right example isn’t -- the right example would cause crawling and indexing of duplicative content.


2. Structure URLs for infinite scroll search engine processing.
   • Each component page contains a full URL. We recommend full URLs in this situation to minimize potential for configuration error.
     • Good: example.com/category?name=fun-items&page=1
     • Good: example.com/fun-items?lastid=567
     • Less optimal: example.com/fun-items#1
     • Test that each component page (the URL) works to take anyone directly to the content and is accessible/referenceable in a browser without the same cookie or user history.
   • Any key/value URL parameters should follow these recommendations:
     • Be sure the URL shows conceptually the same content two weeks from now.
       • Avoid relative-time based URL parameters:
         example.com/category/page.php?name=fun-items&days-ago=3
     • Create parameters that can surface valuable content to searchers.
       
       • Avoid non-searcher valuable parameters as the primary method to access content:
         example.com/fun-places?radius=5&lat=40.71&long=-73.40


3. Configure pagination with each component page containing rel=next and rel=prev values in the <head>. Pagination values in the <body> will be ignored for Google indexing purposes because they could be created with user-generated content (not intended by the webmaster).


4. Implement replaceState/pushState on the infinite scroll page. (The decision to use one or both is up to you and your site’s user behavior). That said, we recommend including pushState (by itself, or in conjunction with replaceState) for the following:
   • Any user action that resembles a click or actively turning a page.
   • To provide users with the ability to serially backup through the most recently paginated content.


5. Test!
   • Check that page values adjust as the user scrolls up or down. John Mueller’s infinite-scroll-with-pagination site demonstrates the scrolling up/down behavior.
   • Verify that pages that are out-of-bounds in the series return a 404 response (i.e., example.com/category?name=fun-items&page=999 should return a 404 response if there are only 998 pages of content).
   • Investigate potential usability implications introduced by your infinite scroll implementation.

Written, reviewed, or coded by John Mueller, Maile Ohye, and Joachim Kupke

Faceted navigation best (and 5 of the worst) practices

Webmaster Level: Advanced

Faceted navigation, such as filtering by color or price range, can be helpful for your visitors, but it’s often not search-friendly since it creates many combinations of URLs with duplicative content. With duplicative URLs, search engines may not crawl new or updated unique content as quickly, and/or they may not index a page accurately because indexing signals are diluted between the duplicate versions. To reduce these issues and help faceted navigation sites become as search-friendly as possible, we’d like to:

• Provide background and potential issues with faceted navigation
• Highlight worst practices
• Share best practices
  • New faceted navigation implementations or redesigns
  • Existing faceted navigation implementations

Selecting filters with faceted navigation can cause many URL combinations, such as http://www.example.com/category.php?category=gummy-candies&price=5-10&price=over-10

Background

In an ideal state, unique content -- whether an individual product/article or a category of products/articles --  would have only one accessible URL. This URL would have a clear click path, or route to the content from within the site, accessible by clicking from the homepage or a category page.

Ideal for searchers and Google Search

• Clear path that reaches all individual product/article pages
  
  
  
  On the left is potential user navigation on the site (i.e., the click path), on the right are the pages accessed.
  
  
  
• One representative URL for category page
  http://www.example.com/category.php?category=gummy-candies
  
  
  
  Category page for gummy candies
  
  
  
• One representative URL for individual product page
  http://www.example.com/product.php?item=swedish-fish
  
  
  Product page for swedish fish

Undesirable duplication caused with faceted navigation

• Numerous URLs for the same article/product
  
  

  Canonical	Duplicate
  example.com/product.php? item=swedish-fish	example.com/product.php? item=swedish-fish&category=gummy-candies&price=5-10

  Same product page for swedish fish can be available on multiple URLs.
  
  
• Numerous category pages that provide little or no value to searchers and search engines)
  
  

  URL	example.com/category.php? category=gummy-candies&taste=sour&price=5-10	example.com/category.php? category=gummy-candies&taste=sour&price=over-10
  Issues	No added value to Google searchers given users rarely search for [sour gummy candy price five to ten dollars]. No added value for search engine crawlers that discover same item ("fruit salad") from parent category pages (either “gummy candies” or “sour gummy candies”). Negative value to site owner who may have indexing signals diluted between numerous versions of the same category. Negative value to site owner with respect to serving bandwidth and losing crawler capacity to duplicative content rather than new or updated pages.	No value for search engines (should have 404 response code). Negative value to searchers.

Worst (search un-friendly) practices for faceted navigation

Worst practice #1: Non-standard URL encoding for parameters, like commas or brackets, instead of “key=value&” pairs.

Worst practices:

• example.com/category?[category:gummy-candy][sort:price-low-to-high][sid:789]
• key=value pairs marked with : rather than =
• multiple parameters appended with [ ] rather than &
• example.com/category?category,gummy-candy,,sort,lowtohigh,,sid,789
• key=value pairs marked with a , rather than =
• multiple parameters appended with ,, rather than &

Best practice:

example.com/category?category=gummy-candy&sort=low-to-high&sid=789

While humans may be able to decode odd URL parameters, such as “,,”, crawlers have difficulty interpreting URL parameters when they’re implemented in a non-standard fashion. Software engineer on Google’s Crawling Team, Mehmet Aktuna, says “Using non-standard encoding is just asking for trouble.” Instead, connect key=value pairs with an equal sign (=) and append multiple parameters with an ampersand (&).

Worst practice #2: Using directories or file paths rather than parameters to list values that don’t change page content.

Worst practice:

example.com/c123/s789/product?swedish-fish
(where /c123/ is a category, /s789/ is a sessionID that doesn’t change page content)

Good practice:

example.com/gummy-candy/product?item=swedish-fish&sid=789 (the directory, /gummy-candy/,changes the page content in a meaningful way)

Best practice:

example.com/product?item=swedish-fish&category=gummy-candy&sid=789 (URL parameters allow more flexibility for search engines to determine how to crawl efficiently)

It’s difficult for automated programs, like search engine crawlers, to differentiate useful values (e.g., “gummy-candy”) from the useless ones (e.g., “sessionID”) when values are placed directly in the path. On the other hand, URL parameters provide flexibility for search engines to quickly test and determine when a given value doesn’t require the crawler access all variations.

Common values that don’t change page content and should be listed as URL parameters include:

• Session IDs
• Tracking IDs
• Referrer IDs
• Timestamp

Worst practice #3: Converting user-generated values into (possibly infinite) URL parameters that are crawlable and indexable, but not useful in search results.

Worst practices (e.g., user-generated values like longitude/latitude or “days ago” as crawlable and indexable URLs):

• example.com/find-a-doctor?radius=15&latitude=40.7565068&longitude=-73.9668408

• example.com/article?category=health&days-ago=7

Best practices:

• example.com/find-a-doctor?city=san-francisco&neighborhood=soma

• example.com/articles?category=health&date=january-10-2014

Rather than allow user-generated values to create crawlable URLs  -- which leads to infinite possibilities with very little value to searchers -- perhaps publish category pages for the most popular values, then include additional information so the page provides more value than an ordinary search results page. Alternatively, consider placing user-generated values in a separate directory and then robots.txt disallow crawling of that directory.

• example.com/filtering/find-a-doctor?radius=15&latitude=40.7565068&longitude=-73.9668408
• example.com/filtering/articles?category=health&days-ago=7

with robots.txt:

User-agent: *
Disallow: /filtering/

Worst practice #4: Appending URL parameters without logic.

Worst practices:

• example.com/gummy-candy/lollipops/gummy-candy/gummy-candy/product?swedish-fish
• example.com/product?cat=gummy-candy&cat=lollipops&cat=gummy-candy&cat=gummy-candy&item=swedish-fish

Better practice:

example.com/gummy-candy/product?item=swedish-fish

Best practice:

example.com/product?item=swedish-fish&category=gummy-candy

Extraneous URL parameters only increase duplication, causing less efficient crawling and indexing. Therefore, consider stripping unnecessary URL parameters and performing your site’s “internal housekeeping”  before generating the URL. If many parameters are required for the user session, perhaps hide the information in a cookie rather than continually append values like cat=gummy-candy&cat=lollipops&cat=gummy-candy& ...

Worst practice #5: Offering further refinement (filtering) when there are zero results.

Worst practice:

Allowing users to select filters when zero items exist for the refinement.

Refinement to a page with zero results (e.g., price=over-10) is allowed even though it frustrates users and causes unnecessary issues for search engines.

Best practice

Only create links/URLs when it’s a valid user-selection (items exist). With zero items, grey out filtering options. To further improve usability, consider adding item counts next to each filter.

Refinement to a page with zero results (e.g., price=over-10) isn’t allowed, preventing users from making an unnecessary click and search engine crawlers from accessing a non-useful page.

Prevent useless URLs and minimize the crawl space by only creating URLs when products exist. This helps users to stay engaged on your site (fewer clicks on the back button when no products exist), and helps minimize potential URLs known to crawlers. Furthermore, if a page isn’t just temporarily out-of-stock, but is unlikely to ever contain useful content, consider returning a 404 status code. With the 404 response, you can include a helpful message to users with more navigation options or a search box to find related products.

Best practices for new faceted navigation implementations or redesigns

New sites that are considering implementing faceted navigation have several options to optimize the “crawl space” (the totality of URLs on your site known to Googlebot) for unique content pages, reduce crawling of duplicative pages, and consolidate indexing signals.

• Determine which URL parameters are required for search engines to crawl every individual content page (i.e., determine what parameters are required to create at least one click-path to each item). Required parameters may include item-id, category-id, page, etc.
• Determine which parameters would be valuable to searchers and their queries, and which would likely only cause duplication with unnecessary crawling or indexing. In the candy store example, I may find the URL parameter “taste” to be valuable to searchers for queries like [sour gummy candies] which could show the result example.com/category.php?category=gummy-candies&taste=sour. However, I may consider the parameter “price” to only cause duplication, such as category=gummy-candies&taste=sour&price=over-10. Other common examples:
• Valuable parameters to searchers: item-id, category-id, name, brand...
• Unnecessary parameters: session-id, price-range...
• Consider implementing one of several configuration options for URLs that contain unnecessary parameters. Just make sure that the unnecessary URL parameters are never required in a crawler or user’s click path to reach each individual product!
  
  
  • Option 1: rel="nofollow" internal links

    Make all unnecessary URLs links rel=“nofollow.” This option minimizes the crawler’s discovery of unnecessary URLs and therefore reduces the potentially explosive crawl space (URLs known to the crawler) that can occur with faceted navigation. rel=”nofollow” doesn’t prevent the unnecessary URLs from being crawled (only a robots.txt disallow prevents crawling). By allowing them to be crawled, however, you can consolidate indexing signals from the unnecessary URLs with a searcher-valuable URL by adding rel=”canonical” from the unnecessary URL to a superset URL (e.g. example.com/category.php?category=gummy-candies&taste=sour&price=5-10 can specify a rel=”canonical” to the superset sour gummy candies view-all page at example.com/category.php?category=gummy-candies&taste=sour&page=all).

  • Option 2: Robots.txt disallow

    For URLs with unnecessary parameters, include a /filtering/directory that will be robots.txt disallow’d. This lets all search engines freely crawl good content, but will prevent crawling of the unwanted URLs. For instance, if my valuable parameters were item, category, and taste, and my unnecessary parameters were session-id and price. I may have the URL:
    example.com/category.php?category=gummy-candies
    which could link to another URL valuable parameter such as taste:
    example.com/category.php?category=gummy-candies&taste=sour.
    but for the unnecessary parameters, such as price, the URL includes a predefined directory, /filtering/:
    example.com/filtering/category.php?category=gummy-candies&price=5-10
    which is then robots.txt disallowed

    User-agent: *
Disallow: /filtering/

  • Option 3: Separate hosts

    If you’re not using a CDN (sites using CDNs don’t have this flexibility easily available in Webmaster Tools), consider placing any URLs with unnecessary parameters on a separate host -- for example, creating main host www.example.com and secondary host, www2.example.com. On the secondary host (www2), set the Crawl rate in Webmaster Tools to “low” while keeping the main host’s crawl rate as high as possible. This would allow for more full crawling of the main host URLs and reduces Googlebot’s focus on your unnecessary URLs.

    • Be sure there remains at least one click path to all items on the main host.
    • If you’d like to consolidate indexing signals, consider adding rel=”canonical” from the secondary host to a superset URL on the main host (e.g. www2.example.com/category.php?category=gummy-candies&taste=sour&price=5-10 may specify a rel=”canonical” to the superset “sour gummy candies” view-all page, www.example.com/category.php?category=gummy-candies&taste=sour&page=all).

• Prevent clickable links when no products exist for the category/filter.
• Add logic to the display of URL parameters.
• Remove unnecessary parameters rather than continuously append values.
• Avoid
  example.com/product?cat=gummy-candy&cat=lollipops&cat=gummy-candy&item=swedish-fish)
• Help the searcher experience by keeping a consistent parameter order based on searcher-valuable parameters listed first (as the URL may be visible in search results) and searcher-irrelevant parameters last (e.g., session ID).
• Avoid
  example.com/category.php?session-id=123&tracking-id=456&category=gummy-candies&taste=sour
• Improve indexing of individual content pages with rel=”canonical” to the preferred version of a page. rel=”canonical” can be used across hostnames or domains.
• Improve indexing of paginated content (such as page=1 and page=2 of the category “gummy candies”) by either:
• Adding rel=”canonical” from individual component pages in the series to the category’s “view-all” page (e.g. page=1, page=2, and page=3 of “gummy candies” with rel=”canonical” to category=gummy-candies&page=all) while making sure that it’s still a good searcher experience (e.g., the page loads quickly).
• Using pagination markup with rel=”next” and rel=”prev” to consolidate indexing properties, such as links, from the component pages/URLs to the series as a whole.
• Be sure that if using JavaScript to dynamically sort/filter/hide content without updating the URL, there still exists URLs on your site that searchers would find valuable, such as main category and product pages that can be crawled and indexed. For instance, avoid using only the homepage (i.e., one URL) for your entire site with JavaScript to dynamically change content with user navigation --  this would unfortunately provide searchers with only one URL to reach all of your content. Also, check that performance isn’t negatively affected with dynamic filtering, as this could undermine the user experience.
• Include only canonical URLs in Sitemaps.

Best practices for existing sites with faceted navigation

First, know that the best practices listed above (e.g., rel=”nofollow” for unnecessary URLs) still apply if/when you’re able to implement a larger redesign. Otherwise, with existing faceted navigation, it’s likely that a large crawl space was already discovered by search engines. Therefore, focus on reducing further growth of unnecessary pages crawled by Googlebot and consolidating indexing signals.

• Use parameters (when possible) with standard encoding and key=value pairs.
• Verify that values that don’t change page content, such as session IDs, are implemented as standard key=value pairs, not directories
• Prevent clickable anchors when products exist for the category/filter (i.e., don’t allow clicks or URLs to be created when no items exist for the filter)
• Add logic to the display of URL parameters
• Remove unnecessary parameters rather than continuously append values (e.g., avoid example.com/product?cat=gummy-candy&cat=lollipops&cat=gummy-candy&item=swedish-fish)
• Help the searcher experience by keeping a consistent parameter order based on searcher-valuable parameters listed first (as the URL may be visible in search results) and searcher-irrelevant parameters last (e.g., avoid example.com/category?session-id=123&tracking-id=456&category=gummy-candies&taste=sour& in favor of example.com/category.php?category=gummy-candies&taste=sour&session-id=123&tracking-id=456)
• Configure Webmaster Tools URL Parameters if you have strong understanding of the URL parameter behavior on your site (make sure that there is still a clear click path to each individual item/article). For instance, with URL Parameters in Webmaster Tools, you can list the parameter name, the parameters effect on the page content, and how you’d like Googlebot to crawl URLs containing the parameter.
  
  
  
  URL Parameters in Webmaster Tools allows the site owner to provide information about the site’s parameters and recommendations for Googlebot’s behavior.


• Be sure that if using JavaScript to dynamically sort/filter/hide content without updating the URL, there still exists URLs on your site that searchers would find valuable, such as main category and product pages that can be crawled and indexed. For instance, avoid using only the homepage (i.e., one URL) for your entire site with JavaScript to dynamically change content with user navigation --  this would unfortunately provide searchers with only one URL to reach all of your content. Also, check that performance isn’t negatively affected with dynamic filtering, as this could undermine the user experience.
• Improve indexing of individual content pages with rel=”canonical” to the preferred version of a page. rel=”canonical” can be used across hostnames or domains.
• Improve indexing of paginated content (such as page=1 and page=2 of the category “gummy candies”) by either:
• Adding rel=”canonical” from individual component pages in the series to the category’s “view-all” page (e.g. page=1, page=2, and page=3 of “gummy candies” with rel=”canonical” to category=gummy-candies&page=all) while making sure that it’s still a good searcher experience (e.g., the page loads quickly).
• Using pagination markup with rel=”next” and rel=”prev” to consolidate indexing properties, such as links, from the component pages/URLs to the series as a whole.
• Include only canonical URLs in Sitemaps.

Remember that commonly, the simpler you can keep it, the better. Questions? Please ask in our Webmaster discussion forum.

Written by Maile Ohye, Developer Programs Tech Lead, and Mehmet Aktuna, Crawl Team