Here are some examples of online collaboration experiments that are interesting. Some are fun to watch, and all are interesting to study, not from a technology point of view, but rather from how few people use/abuse the privilege behind the anonymity the internet provides.

First, visit the The Scratchpad, which is a Flash application. People draw on the same whiteboard simultaneously. The whiteboard clears itself every 2 minutes, and the whole thing starts over. The results are interesting, ranging from childish name calling to exquisite works of art that leave all others just watching the artist drawing.

Then, visit the Smaller Picture, where the "collective conciousness" is presented with the name of an object, and asked whether a particular pixel should be black or white. Each visitor can choose a different pixel.

Finally, visit Pixelfest, which also allows you to place a pixel in a collective drawing, but in any color you want.