Talk about new ways to collaborate: Greg Elin's Fotowiki lets you upload and annotate photos in a wiki-like format.  It sticks close to traditional wiki values like ease of creating pages, equal editing capabilities for everyone, etc.  But the best thing about it?  The ability to select and annotate just part of the photo, instead of trying to describe in words exactly what you're talking about in the picture.  ("See that guy to the left of the girl with the hat?"  Not anymore!) 

Of course, because the interface is graphical, the number of comments possible on any one photo is limited by screen real estate.  I'm not sure that's a bad thing, though: because anyone can edit or delete annotations, "junk" or unfocused comments will tend to get removed by the community, since screen space becomes a premium commodity.  I'd be curious to see how this plays out in practice as more people use the system.

Overall, a very slick solution to the problem of creating graphics-native forms of collaboration that isn't just another shared whiteboard.

Update: The original idea was discussed on the WikiForum mailing list, archived here.  (Thanks, Sunir!)