This might be naive, but a monthly subscription model might work for facebook. Then you'd have no more ads, no more privacy snafus--the goals of the company would be aligned with the goals of the users because the users would be customers. It's simple. Would it tick off some users? Sure, but that hasn't stopped facebook in the past.

I'd pay $10/month for a facebook that cares about me as a customer. Right now I don't use it because facebook's goals aren't aligned with mine, even though it's a valuable service.

But $10/month per user probably wouldn't be enough revenue to match facebook's high valuation.