According to Wikipedia, social movements are a type of group action. What better group action than a free encyclopedia with millions of volunteer members. Wikipedia never meant to become a movement but it did.
With the rise of the Internet and free, open-sourced technology, Wikipedia has evolved well beyond an encyclopedia. While Wikipedia may not fit the current definition of social movement, that is what's so remarkable about it; the site is helping to redefine the term and update the process of Social Movement. It promotes online activism and human expression in a way the world has never seen. WIth its huge audience, Wikipedia is even being recognized as an important element in how public figures, like presidential candidates, are perceived online.
Whether we agree Wikipedia is a social movement or not, it's certainly the largest online community gathering with a pride and sense of human responsibility that the world has ever seen.