Webmaster Central back in August 2006, with a goal of creating a place for us to learn more about Google's crawling and indexing of websites, and to offer tools for submitting sitemaps and other content.
Google has also been working to roll out exciting new features for Webmaster Tools, like internal/external links data and the Message Center, over the past year.
Anyone who is NOT paying attention to these tools is simply silly. Google are happy to give you all the stats for what they see on your site and it's VITAL that Google ahs a good handle on all your pages.
Read about their new Webmaster Tools features here on the Official Google Webmaster Central Blog.