So what is webspam anyway?
Matt Cutts is the head of Webspam for Google and in this episode he shares his tips for ranking well in Google. (For the record, starting a blog was one of his highest priority tips.)
We spend a fair amount of time validating the fact that blogs will help you rank higher in the search indexes. That’s enough ROI to do it.
He also confirmed that the meta description tag and alt attributes are currently used by Google. In fact, we cover most of the on page code tags and attributes.
Also, pay close attention to the riff on sitemaps and Sitemap.org.