"With a newsreader, you're just reading a bunch of weblogs with the sidebars stripped off, all on one page. With an aggregator, you can force all your friends and idols to get together and write a collaborative weblog, even if they don't know each other (or do, and can't stand each other). If somebody isn't in the mood to post for a while, no problem: the rest can pick up the slack."
This relates to a post I made a while back challenging Dave's argument that it's not an aggregator unless it mixes the content sources up on a single page. Phil seems to agree (with Dave). While I appreciate the time-saving factor, In my (limited) experience reading blogs like that, I've found it disorienting because the posts lack their normal context (this would probably lessen if people were writing with aggregators in mind). Nonetheless, I find the idea intriguing, as it maps directly to some things I've wanted to build for a long time. Hopefully, I'll know more soon.