I think it is becoming increasing clear, especially with the Yahoo patent suit, that Facebook desperately needs a patent portfolio. Additionally, what makes you so certain Facebook doesn't needs patents? Please, explain.

If they need a patent portfolio is beside the point. They don’t have a browser and are shopping for one, any patents they acquire would only be a bonus at that time.

Why does Facebook need a browser? This is a space I would honestly never consider them "innovating" in.