Two people I respect greatly have recently commented about Facebook and really all social networking. Eliot Pierce who has been a force for good at NY Times Online says he's in the "Facebook is not a business" camp.
Alan Meckler, CEO of Jupitermedia, blogged about about it here pointing out that value will be in vertical social networking (see my earlier post about sphinn). Alan has made a number of fortunes by providing targeted information to niche audiences and brokering this audience to relevant sponsors. I suggested to Alan that he should start or buy a site that would appeal to interactive marketers who are beginning to include social networks in their media buys (agencies are assigning full-time specialists to them). Generally Alan is skeptical about the true (and long-term) value of generalist sites like Facebook.
Have a look at the discussion thread following a post by Fred Wilson which reinforces Alan's point.
There is no seamless approach to anything these days. Key to technology project success is proper stitching of the seams based on thoughtful planning. The same will hold true with social media - it will be the social middleware that will enable vertical communities to reach outside "the club" as needed. How the middleware providers make money while the networks own the page views is beyond me at this point.