Ask Search Blogs is cool.
Ask owns Bloglines, my primary . Bloglines is currently indexing over 1.5 billion archived posts – searching for what people subscribe to. So instead of using net crawlers to discover links, the Bloglines subscriber indexing efforts should eventually generate more useful results than other blog/feed search sites.
The results page allows you to subscribe to the feed or post to sites like digg and del.icio.us.
[tags]search engines[/tags]