And that's the important bit, people seem to either check FB mail directly or read it in there own email. Either way you've got more chance of getting through to them soon if you send via Facebook... I don't like it either though, it makes me rather uncofortable to have more comunication going through FB.

My experience with non-geeky friends is that they check facebook for messages and interact with friend/family through comments and wall-posts. Some of them get email notifications for these things but they use them as a prompt to go to facebook.com to view and respond. Email is the medium but not the message.