I just joined the Yahoo Aggregators Group... What a riot. There's only like 96 messages, so I decided to start from the beginning and read what had been posted up til now. Within the first five messages, a flame war breaks out between Morbus the AmphetaDesk guy and Dave Winer. Quite amusing.
Lots of interesting people who are part of this group. Look for aggregators to be a dime a dozen pretty soon.