In one place search yahoo, Google, Technorati, WordPress.com, YouTube and lots of others. Punch in a term, see the top results from a whole bunch of useful sites. Great idea. Hat tip Seth Godin.
Does what it says on the tin, blends feeds. Give it a bunch of feed urls and it'll whip up together into one rich, dark, feed smoothie!
FriendFeed aggregates your friends data from many web services. Receive updates of your friends on flickr, twitter, their blog, amazon wishlist, etc, etc. The whole thing is aggregated into one single feed.