I read this the other day: O’Reilly Network: Stewart Butterfield on Flickr and I just had to join. If you’re into digital photography at all, I highly recommend it. One of the really sweet things are the Folksonomic tags. You can browse the 150 most popular tags here or my tags here. e.g. Flickr: Photos tagged with boccioni (You’re the only person who has used “boccioni” as a tag.)

Also, check out the groups where users pools their photos. A thematic one called squared circle is pretty neat and makes for a great slideshow.