The more I think about it, the more it looks like a case of "we need to improve our demographics. Let's add the kind of social networking features that appeal to the Facebook generation. Our loyal fans already love us and these new features will attract new fans." So they looked at what those Facebookers enjoy and made a laundry list.
What wasn't considered enough was "will any of the new features disrupt TT or alienate our current base?" It's very speculative, but I can see some young programmer saying "I love this feature I am adding, therefore everyone will."

