I was reading one of my favourite blogs today, and found a link to a kind of on-line collaboration! 140 in a bottle is a relatively new application on Twitter. All you have to do is to type your message into a "bottle" and send it "out to sea". A random Twitter user will get your anonymous message within 90 days. You can even add a photo - how great is that? :)
140InABottle: http://140inabottle.com/index.php
