Great article in The Guardian on Socialtext by David Tebbutt, not only for enterprise collaboration, but how it augmented the Les Blogs event (hat tip: Loic).
Similarly, Kevin Werbach hosted a pre-Supernova party this Tuesday. When Kevin made a toast he pointed out how it felt like a bubble event, but the key difference was how everyone chipped in $25 through paypal on the wiki signup page. Good examples of easy (and cost-effective) group forming.
