Update: This article is published in 2007. Nowadays XML sitemaps have found there way into our WordPress SEO plugin and we do recommend using them for any (larger) site.
First of all: I do want you to use Google Webmaster Tools. It’s an incredible useful toolbox, so please, please use it. If you’re not using it at the moment, check out my post on how to use Google Webmaster Tools. I do think though, that XML Sitemaps (whether it be Google sitemaps or otherwise),Â are not doing you any good in most cases…
My arguments for it aren’t new. Dave has made it very clear why an XML sitemap is BAD. It’s basically throwing away very valuable data… Up until now, you don’t have a real problem when you’re using an XML sitemap, as Google will throw badly linked pages into the supplemental index, you can check that, and see where you’re going wrong. The scary thing is though, that Google has already shut down the query with which you could request all supplemental pages. A query which, as Rand pointed out while requesting the return of the supplemental query, was very valuable.
Google still shows the “Supplemental Result” tag though, so there are still ways to find out if a page is linked well enough… However, if you read the comment thread on the article on SEOmoz above, you will see Matt Cutts saying:
As I mentioned at SMX Seattle, my personal preference would be to drop the “Supplemental Result” tag altogether.
Now if that happens (and with Matt saying this, there’s a good chance of that), how will you know which of the pages you’ve pushed into Google’s index through it’s own “shortcut”, are not receiving the linklove they need?
In white hat SEO, there are hardly any shortcuts to take, and you should think at least twice before taking one… The XML sitemaps might get you indexed faster, but they won’t make you rank any better. In my opinion, there’s only one reason to use XML sitemaps, and that’s if you’ve got a news site and need your news in Google’s index FAST to get the maximum amount of traffic out of it. This will only work if your site has the authority one needs to make sure a new article will start ranking immediately, and it would mean you should only put your news articles into the XML sitemap.
For any other purpose, I would suggest to throw away your XML sitemap now, and start using the data that Google gives you for free: check which pages get indexed when, and try to find the patterns in it.