Most people are too shy to get out there and do real activism, but you should be aware there’s always something you can do. Even the smallest thing helps, especially when you get a large number of people doing the same thing.
A mate of mine who goes by the online name Drunken Madman has come up with a brilliant idea (inspired by this) for a bit of small-time online activism anyone can do, so I’d like to promote the idea as well and get as many people onboard as possible.
If you use any geolocation services such as Foursquare, then you’re all set. I’m sure there’s plenty of other similar services out there, so choose which ever one suits you.
You can read the full details of this small bit of online activism at his blog, My Colleagues are Idiots. If you’re curious about the phrase he’s put forward (this phrase is especially for chiropractors), then take a gander at LibelReform.org and Sense About Science and get tagging.