An article in the Guardian from Cory Doctorow, pointing out the (possibly) obvious fact that networks are a necessary but far from sufficient cause of social change. Facebook, Twitter, et al do not cause revolutions like those seen recently in the middle east, but they certainly help to spread the word around.

A good antidote to over-enthusiastic posts that suggest social networks will change the world - e.g. this or this. People change the world, not social networks. Social networks make it easier for more people to connect, communicate and share in a more egalitarian way than ever before, but other forces and other (hierarchical and centralised) media still matter.