I've just published the talk I delivered to the Sydney Atheists on Online Activism to Slideshare. It doesn't work perfectly, since some of the slides were animated, but the overview looks something like this:
Online Activism 101
View more presentations from Jason Brown.
If all goes to plan, this will also be presented as a podcast from Sydney Atheists, so you can listen to me ramble as you read the slides.
If you'd like a talk like this delivered at your skeptical, atheist, humanist or freethinkers group, please let me know. I'm also working up a more specific "Skeptical Social Media" talk and can...