well, that is one thing that will definitely set it apart from tumblr. hopefully they can use it to carve out a good niche.
Posterous had a lightning start, then fell on its ass; Tumblr adopted its best features and did them better. I mean, Posterous is here bragging about allowing minor thematic changes. I've had complete HTML control of my tumblelogs for three years. Not to mention, Tumblr's default theme is not only more cutting-edge than Posterous's, it's also vastly more attractive.
The bigger idea here is being able to autopost as a group, which has not been done before as far as I know -- it's great for team twitter accounts, for instance.
Falling on its ass is rather insulting, and also totally untrue.
Rory, please chill out.
"When each of us posts to the group, we can choose to have it post to our own autopost destinations."