Erick Schonfeld:

The advantage Facebook could have in the Q&A space is that to the extent that you find answers from your extended social network, questions can become the start of deeper conversations and spur new relationships. But breaking it out as a separate feature raises some new questions. Will every major type of status update now become its own feature on Facebook (like Photo and Event updates do)? And, if so, what’s next?

I see this as a move to counter the growing popularity of sites like Formspring.me who are very popular among younger students (middle school to high school).