Just read Collective Apathy and the Internet and Yvain's comment about examples when it ('the internet') work in coordinating group action. Apparently sometimes it does and it may depend on a few things like critical mass, attention span, identity, emotionality.

Let's try a poll.

I think that the internet works starts to work when...

...critical mass of community is

...effect is visible

How relevant do you think are the following effects for the success

Interesting/new

Outrageous

Differing from standard norms

Sad

Very beneficial for larger cause

What are your ideas? When does the internet work at coordination and when doesn't it?