EDIT - Solution:
[url=http://www.bungie.net/en-us/Forum/Post?id=60809347&path=1]Achronos[/url]: If you don't want bungie.net being able to see the online status of your Facebook friends, go to Facebook's application permission page and revoke Bungie.net's permission to see your friend's presence information (don't remove the entire "app", just the one permission).
As I'm always signed into it, I linked my Bungie account to Facebook so that I could quickly login without needing to punch in my Hotmail/PSN details. What's been bugging me though, is the 'online friends' button on the nav-bar shows which of my [i]facebook[/i] friends are online.
I'm not sure about anyone else - but the vast majority of my facebook friends are not gamers, and I don't really want or need to know how many of them are online.
[b]Is there a way - or could there be an option to set the 'Friends Online' button on the nav-bar to [i]not[/i] show Facebook friends? Instead, only XBL/PSN friends?[/b]
(Note: A strange quirk too: I have 'facebook chat' off by default; so Bungie.net must somehow bypass my settings on facebook?)