Google actually has rolled out a small step towards this. They recognize microformats and other bits of structured data, and use them to do things like supply the number of stars for a review or to populate friend lists for social networking sites.

Their official jargon is "Rich Snippets", and they have a couple posts on it at http://googlewebmastercentral.blogspot.com/2009/05/introduci... and http://googlewebmastercentral.blogspot.com/2009/10/help-us-m... .