I’ve been wondering when Google would get around to this. A few days ago they announced Google Blog Search, which indexes blog entries based on RSS or Atom feeds.
Google’s playing catch-up to smaller services like Technorati, but seem to have scooped Yahoo! and MSN, both of whom have been rumored to be coming out with an RSS-feed search “any day now” for months (Yahoo! even briefly revealed a test page before they realized it wasn’t being firewalled properly).
One feature Google gets right is that every page includes a link to subscribe to an RSS or Atom feed on that query, essentially turning any search phrase into an aggregator. Technorati has something similar with their watchlists, but you have to create an account and go through their page to create a new standing query. Google just creates the contents on the fly &mash; a big win in terms of ease-of-use since you’re likely to most want a standing query after you’ve just done the search as a regular one.
(Discovered via Political Animal, of all places, but there are also announcements at SixApart and John Battelle’s Searchblog.)