Charlie and I are developing a course for American Management Association called Making Sense of Web 2.0: Levaraging Social Media in Your Organization. (The consensus was that social computing - while perhaps more accurate than social media - sounds too geeky.) But regardless of what you call it, the modern web is mostly about mindset.
Web 2.0 is familiar turf for marketers, project managers, consultants and developers. There are many, many fantastic examples of how it's used with internal and external audiences.
But when you cut past the flash, Web 2.0 works best when we stop selling and telling and engage in listening and learning.
It sounds so simple: we need to treat customers as people with something valuable to say. We need to treat employees as responsible adults. But how many organizations actually do? After all, there aren't any extra "Hay points" in it. And it could get us in trouble. Not much of an incentive there for the average corporate soldier.
You may want to look into Pfizerpedia (Pfizer's version of wikipedia). You can read about it on a number of sites. I'd like to suggest Karl Kapp's blog. Considering the sensitivities of large corporations, with signficant investment in intellectual property, in a highly regulated industry in which compliance dominates behavior, accustomed to strictly following processes and protocol -embracing Web 2.0 is nothing short of a major shift in mindset. Even though I've given away the plot, I still highly recommend the movie:
The current economic crisis may reveal that companies really see Web 2.0 as a "nice to have" rather than the necessity it is for "keeping the lights on." If so, those companies may have snazzy Web 2.0 sites - but not a Web 2.0 mindset.