Twibbon overlays a small icon on your profile image to show support for some cause, organization, product or movement. Once you affiliate with something it does use your account to send a notice out to al of your followers, so be careful what you choose.
You can find trending causes if you just have to show support for something hot, or even create your own movement. For the geeks, there is a whole technology area and some recent ones are Android, Ubuntu, Lotus Notes and even Python. Why not grow someones else’s product?
Seriously, we do see value in using your avatar speak for a cause and showing support in any way you can. It would be nice if it cost a dollar or so to use the service and proceeds were donated to that very cause.