Did twitter, social media, cause the revolutions in Tunisia & Egypt?

There's been a lot of discussion about the role of social media in the uprisings the past few weeks in the Arab/Muslim world. The Globe and Mail has a series of "curated" posts (from facebook, twitter, etc.) about what's been happening in Egypt here and the Huffington Post also has a guide to what's going on in Egypt here. I've also been posting a lot of links of my twitter feed. Here are three different views on the usefulness of social media: from a Forbes magazine blog, from the Globe, and from boingboing. Note that all of these are Western-based media (although I was quoted on a Cairo blog on the weekend). What do you think? We'll talk about this in lecture on Thursday, so take a look at these links and come to class.