All the cool kids know by now, since there was a blog entry on it, however, I just got to that point in my feed reader, so I'm all excited like it isn't 2 days old. =]
The gist of it is that they've made TwitterFeed obsolete for Posterous blogs, and also made images uploaded with posts autopost to Flickr. The second is the most awesome of the two, because it means I don't have to write a script to do it myself. Now I'm just waiting for them to do an autopost to LiveJournal, so that I don't need my script anymore.
Oh, yeah, and tags on posts would be totally awesome. (That's gotta be my #1 wanted feature.) But at least my name is unique, so using the search box on the explore page with my search term prefixed with 'ajani' finds me old posts pretty fast. (Actually, it would be awesome if I could embed that search box in the sidebar of my blog. =)