I don't think you're thinking it through. Facebook is setting up a situation where it can do bargain barrel corp dev -- acquihires or (what reasonable folks would consider) theft of IP based on what technology was used to build the target's "About Us" page.
No, they're setting up a situation where if Yahoo sues them for some one-click patent they can be like, "well, you're using our virtual dom patent so let's call the whole thing off"
