Mike has a great post asking (in a very Seinfeld-esque way) what's the big deal with FriendFeed?
For those not familiar, FriendFeed is a social aggregation site collates all the variouos feeds from all your various friends, and adds comment functionality. In other words, it's a way to combine all the lifestreams of all your peeps.
I've created a FriendFeed (here), but — like Mike — I just don't get it.
My biggest complaint would be that FriendFeed doesn't offer more than just the titles from most feeds. If you post from your blog, for example, only the post title is represented. Ideally FriendFeed would honor full-content feeds (or provide an extended excerpt, at a minimum).
For me, Tumblr is a much better alternative, if for no other reason than it publishes more than just a post title from a feed. Contrast my FriendFeed against my Tumblog and I think you'll agree that my Tumblog is much richer representation of my lifestream than my FriendFeed.
Tumblr doesn't allow commenting at this time, but if I want to comment on your Flickr picture, I'm still very inclined to comment over at Flickr and interact with that full community.