"One way could be to put the last few additions right on the homepage along with the last few collab parts (both with thumbnails)."
this idea we are actually implementing in the new design -- almost exactly! (great minds think alike...) it will have a snapshot of recent activity. we definitely want to incorporate more newsflash-like info into other places cuz we realize that stuff is pretty inaccessible for newbies. (and even most old timers!)
the second idea is great. we used to have a bookmarking thing but it never worked right. there is some other ideas we have that could also use this feature anyway. i like the suggestion (from SNZ's reply) of it being like livejournals friends stuff -- so you can even have the option of making your own favorites/bookmarks publicly viewable.
great stuff! thanks for sharing. keep the thoughts coming, and then i can get to programming them. ouch! haha