They have over 200,000 freelance providers bidding on jobs, and over 6000 active jobs. The oDesk manifesto says better than I could what they do and why they do it. They've assembled a serious management and advisory team that reads like a Silicon Valley fantasy league roster. They're on to what seems like a great idea, and I wish them much success.
The reason I found out about them is even more interesting, to me at least. They recently published a "Top-100" list for resources and blogs for outsourcing. They ranked the Inside Outsource blog in their top-100 list. (I'm number 23, but the list ranking is topical and alphabetic, not hierarchic.) That's great recognition, and certainly a dose of encouragement for me to pick up my pace and post more frequently. Thanks oDesk, for the recognition, and I hope your readers enjoy both the archive and any future insights.