Our head of products shared this little posting from Facebook's developer site. In short, it seems that a growing number of Facebook users prefer to be contacted by good 'ole email rather than Facebook's proprietary email —Facebook's application developers have been pressing to get easier access to their email addresses.
Apparently, even the walled gardens of Facebook aren't enough to extinguish the value of email. Don't get me wrong, I think Facebook's email can readily replace email for some segments of the population. But overall, this posting and the general trends I’m watching indicate that email continues to be relevant, even in the world of social networks.