What is the point of XML site maps?

[pasware]

Given how Google uses Page Rank to pass link juice from one page to the next if Google can only find a page in an XML site map it will have no link juice and appear very low in search results if at all.

The priority in XML sitemaps field also seems pretty much irrelevant to me. Google determines the priority of a page based on the number of inbound links to it. If your site is designed properly the most important pages will have the most links.

The changefreq field could maybe be useful if you have existing pages that are updated regularly. Though it seems to me Google tends to crawl sites often enough that it isn't useful. Plus for most of the web the significant content of an existing page doesn't change regularly, instead new pages are added with new content.

This leaves the lastmod field as being potentially useful. If Google starts each crawl of your site by grabbing the sitemap and then crawls the pages whose lastmod date is newer than its last crawl of the site their crawling could be much more efficient. The site map would not need to contain every single page of the site, just the ones that have changed recently.

From what I've seen most site map generation tools don't do a great job with the fields other than loc. If Google can't trust the priority, changefreq, or lastmod fields they won't put any weight on them.

It seems to me the best way to rank well in Google is by making a good, content-rich site that is easily navigable by real people (and that's just the way Google wants it).

So, what's the point of XML site maps? Does the benefit (if any) outweigh the cost of developing and maintaining them?

[pasware]

Thanks Axial,

I'm not convinced it matters much if Google crawls deep pages they wouldn't find through organic links. If the pages aren't linked to they won't have any link juice and therefore won't rank well in SERPs.

The link about using site maps for canonical URLs says or implies you should only put your most important URLs in the sitemap. The sitemap tools I've seen tend to take a kitchen sink approach, which is needed if you are using it to try to get a deeper crawl. Plus there's no way (I see) in a sitemap to specify that page A is the canonical of page B. They simply suggest telling Google about page A (and not page B) in the hopes page A will get more weight than page B. A canonical meta tag on page B pointing to page A is obviously a much better way to deal with canonicals.

Image and video site maps are potentially valuable. I am asking specifically about site maps for pages.

Specifying related content for a given URL, such as different languages, is indeed useful and not something I was aware of. But it is not applicable on most sites and not used on most site maps.

[AxialDev]

Your sitemap.xml will help googlebot crawl deep pages, but it serves other purposes such as:

• helping Google identify canonical pages: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=139066#3

• creating sitemaps for video, images, etc.: "you can also use Sitemaps to provide Google with metadata about specific types of content on your site, including video, images, mobile, and News. For example, a video Sitemap entry can specify the running time, category, and family-friendly status of a video; an image Sitemap entry can provide information about an image’s subject matter, type, and license." http://support.google.com/webmasters/bin/answer.py?hl=en&hlrm=fr&answer=156184

• you can specify alternate content, such as the URL of a translated page: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=2620865

• and more.

Sometimes working with a sitemap is less risky and maintenance is easier, especially when your CMS is limitative. The 3rd point is a good example. You may also appreciate the centralized approach more from a personnal point of view.

There are good resources on the Google webmaster resources, check them out.

Hope this helps!