Well, what do you know? People are using the internet to express their views! It's almost as though it's the perfect medium for such a thing. Oh wait, it IS the perfect medium. At least in the USA. (Other countries are big into SMS txt messaging - Burma, for example.)
Anyway. If you're into being socially active, want to use the internet, but aren't sure where to start, read Four Steps to Ease You Into Social Web Activism. It will at least give you an idea of some of the technologies out there.
(Source: The Non-Profit Blog Exchange)