I mean, are they really your mates or are they just some random face book "friends" that "know" you because they met a friend of yours once at a party that you happened to be at?
What is the definition of friend exactly?
It's irrelevant however, this is just the difference between private and public notice. I'd call facebook private notice IF privacy settings are set in that way. The people on your 'friends' list on Facebook are there because you approved them to be there and see your posts. However, I'd probably end up sending private messages to a bunch of people ('friends') who I could see myself flying with.
Pyro.
edit: Hah, I like the wordfilter :P