Actually, what will happen is this: I'll start typing "Post" for "post an entry" and it will fill in http://www.livejournal.com/update.bml. Stuff like that. Or I can start by typing in the name of the community, instead of the URL, like just starting with "Who" for who_daily. You do, of course, have to have already been there before for it to work, but it's a very nice feature.