A while back, when I was regularly publishing to multiple sites, I had a thing I called the gFeed that pulled all those feeds (probably a half dozen at my peak) into a single feed.
Sure some people subscribed to it (I believe some still are) but straight aggregation isn’t actually that useful1 – and if you’re crazy enough to want all my feeds, your crazy enough to know how to get them yourself. Soon, FriendFeed will start offering to do the same for you or me, or us.
The value isn’t in the aggregation, it’s in what happens after ther aggregation.
While my exposure to FriendFeed, Streamy, and FeedEachOther is very limited at this point, they all feel too “social network” heavy at this point. Unfortunately, that’s not the biggest missing piece in today’s aggregators.
1. I’ve stopped promoting the gFeed because it’s easier for both of us if I publish more in fewer places.