This question seems to come up a lot still and while I believe sitemaps in general can be great for helping search engine spiders crawl your site and an effective way of spreading out linkjuice (with some nice anchor text) they can also bite you in the arse when not used intelligently. Certainly submitting XML sitemaps specifically to the search engines in my view can have its drawbacks.

sitemaps

Still Won’t Rank

The key reason for submitting a XML sitemap is to help Google crawl your site and find those deep pages. Now those pages may well be included in the index because of the sitemap submission, but the problem is they are still never going to rank for anything. There is a reason why they were not in the index in the first place and Google will simply not start ranking those pages.

Hide The Truth

In many ways sitemaps hide problems or issues with your website. Personally I would only want pages included within the index from my site that ‘should’ be there naturally. Data you get from using the basic site command in Google is more valuable as you can analyse pages or areas of the site that are having problems being crawled and indexed. This then helps you identify problems with site architecture, internal link structure, content etc and resolve issues properly which will help these pages rank.

Overall Site Quality & Trust

Often pages that are merely included in the index because of a sitemap will or can fall into the ‘supplemental index’ results (its still there) which are low pagerank less trusted pages. Now I certainly don’t like the idea of having too many of my sites pages in the supplemental index and showing Google more of your content can mean just that. Instead of Google believing you have 100 pages and only 10 of those are in the supplemental index, your site could now have 200 pages with 100 of those in the supplemental index. So Google is now looking at your overall domain and classing that 50% of your site is not in its view ‘quality content’.

What can that do overall to your domain in terms of authority, trust and rankings?. In this way, you can give too much information to the search engines.

Huge sites with masses of inventory will probably find some of the tools that Webmaster Central can offer extremely valuable, but for the majority of sites there are better things you can spend your time doing than worrying about submitting a sitemap.