Google Sitemaps statistics

I just found out that you can validate your Google Sitemap by placing an empty HTML file on you site. After validation, Google gives you detailed statistics, including _Top Search Queries_ and _Top Search Query Clicks_:
query stats
Even more interesting, they also show crawl statistics with crawl errors and the PageRank distribution for your pages:
crawl stats
Very cool!
[Via Steve Rubel]