May 19th, 2010 by George Aspland
I was contacted by a potential client recently and asked if we could deliver the services quoted by another search marketing firm. The proposal claimed that XML sitemaps help search engine rankings (search positions).
At about the same time yet another client forwarded me an email asking “Do we need this?” It was a message from some SEM company’s sales rep exclaiming “I was unable to locate a “Google Sitemap file” on your website.” It went on to explain that an XML site map “captures all the crucial information about your website, thus facilitating the crawling and indexing process for Google” and that “Google & Yahoo as well recommend that you get a Sitemap file.”
Let’s try to clear up the misinformation about XML site maps.
When to use XML Site maps
XML site maps help get pages indexed
Here is Google’s explanation of XML Site Maps, “Sitemaps are a way to tell Google about pages on your site we might not otherwise discover. In its simplest terms, a XML Sitemap—usually called Sitemap, with a capital S—is a list of the pages on your website. Creating and submitting a Sitemap helps make sure that Google knows about all the pages on your site, including URLs that may not be discoverable by Google’s normal crawling process.”
That last phrase is key “…URL’s that may not be discoverable by Google’s normal crawling process”. If Google, or another search engine, is able to discover a URL in the normal crawling process then also having it listed in a XML site map is of little additional value except in the cases described in the sections below for special content.
A reseller with a large database of products that can’t all be legitimately linked to from other live pages on the site, for example, might employ a XML site map. A XML site map will help get those additional products indexed (But see below about search engine rankings for these products).
Important Note about Automated Site Map Generators – If you are using an XML site map to get pages indexed that are not otherwise reachable by a search engine then you can’t rely on the automated output of many browser based XML site map generators. Most site map generators build the site map by crawling through a web site in much the same way as a search engine does. So if you have pages that search engines can’t crawl then these sitemap generators will not likely be able to reach these pages either. You will need to use a xml site map generator that generates a site map from, for example, your product database or CMS system.
A XML sitemap may help get some new web pages indexed faster, especially for a new site, but as you’ll read about below it won’t help very much with rankings of web pages so you need to decide if it’s worth the effort.
A XML Site MAY help sites with duplicate content/path issues
Google has stated that when you have duplicate content/path issues on a site, issues we see sometimes on dynamically generated sites, including a XML site map that lists only the preferred URL (the Canonical, URL) MAY give the search engines a hint as to which URL to give the most weight to. However it is much better to fix the underlying issue(s) that is causing duplicate content/path issues (see below for more on this).
We employed an XML site map for an ecommerce site with duplicate content/path issues, however we did so many other things at the same to try to help with the issues (changing their mod rewrite procedure, modifying parameter handling in Google’s webmaster tools, fixing 404 error handling, etc) that we really can’t be sure if the XML site map helped or not.
Use XML site maps to give Google additional information about certain web content
You can use site map extensions and specialized site maps to give Google additional information about the certain types of web content. The following overviews are from Google with links to more information in Google’s Webmaster Tools Help -
Video Sitemaps – “One of the best ways to improve your site’s appearance in video search results is to make sure that Google knows about all your rich video content. When you submit a Video Sitemap to Google with all the necessary fields, we will make the included video URLs searchable on Google Video.”
News Sitemap – “A Google News Sitemap is a file that allows you to control which content you submit to Google News. By creating and submitting a Google News Sitemap, you’re able to help Google News discover and crawl your site’s articles”
Mobile Sitemaps – “Google Mobile Sitemaps is an extension of the Sitemap protocol that enables you to submit URLs that serve content for mobile devices into our mobile index. By using Mobile Sitemaps to inform and direct our crawlers, we hope to expand our coverage of the mobile web and speed up the discovery and addition of pages to our mobile index.”
Geo Sitemaps – “Google Geo Sitemaps is an extension of the Sitemap protocol that enables you to publish geospatial content (geographical content) to Google, in order to make it searchable in Google Earth and on Google Maps.”
Additional Image Information – “You can give Google additional details about your images, and provide the URL of images we might not otherwise discover, by adding information to your Sitemap. “
When NOT to use XML Site maps
Don’t use an XML site map as a Band-Aid to fix technical problems.
An XML site map should not be employed because there are pages on the site that aren’t getting indexed for technical reasons. Rather the technical issues should be addressed to get these pages indexed via the regular search engine crawl or they will not likely do well in search engine rankings (read the next section for more on this). Use an XML site map to help get pages indexed that can not be indexed only for valid reasons (see above).
Do Not Use XML Site Maps solely to improve search engine rankings for web pages
An XML site map only helps get a page indexed. It does little to help the rankings (search positions) that these pages will reach. Many SEO’s have tested the affect of site maps on rankings of web pages and none of us have seen much if any effect on rankings (try searching on “XML Sitemap improve rankings?” and you’ll find quite a bit from other SEO’s and see the For More Info section below).
We wouldn’t expect web pages that are only available to search engines via a XML site map to rank very well because of the importance of PageRank (basically an evaluation of the incoming links to a page both from other pages on your site and from other web sites). Pages only available via an XML site map typically do not rank well because the search engine sees no links to the page from other pages within the site or from other web sites.
So, in the example above for a reseller with a large database of products that can’t all be legitimately linked to from other live pages on the site, employing an XML site map site map will help get those additional products indexed. However these pages are not likely to rank well for competitive keyword phrases (unusual or old brand name and model number combinations, for example, may rank well if there’s not much competition for them).
However, providing additional information about some specific web content (such as via the site map extensions and specialized site maps mentioned above) may help rankings by associating the additional information with the content and by highlighting important content (if anyone has some valid tests on this we’d love to see them. We’ll post valid results here).
For More Info
Sitemaps help with universal Search - Dev Basu, writing on Web Marketing Today, gives and overview of the different sitemaps avialable, including image, video, news and Geo sitemaps with tips on how to get started
SEO with Feeds & XML. Lee Odden is a proponent of feeds including XML sitemaps. Here’s his outline of a recent session at SES.
36 SEO Myths That Won’t Die But Need To. See number 4 about XML sitemaps.
Is Most Of SEO Just A Boondoggle? Jill Whelan on XML site maps and a few other issues
Do XML Sitemaps Actually Help? An article by Wesley LeFebvre