I'm descending into particulars here, not to legislate detail in a "you're sinning if you do this" way, but to apply some truth right where you live.
Maybe I'm just personally frustrated with the whole enterprise, but it seems there's more to it...
What are your desires and where is your heart when you are facebook-ing?
One of the problems I've noticed with Facebook is the way it carries unhealthy young person interaction (read Flirting) to the web. (I'll save the distinction between healthy and unhealthy for another day.) Avoiding this is easy (in theory), so here's a suggestion. You know how you can initiate something on fb, you write something, then people respond. Well, just don't respond. Only write your own stuff. Responding sends strong signals of "I'm noticing you" to others. Response equals relationship. This is great in most settings, EXCEPT when a guy is trying to get or keep a girl's attention! What kind of relationship is it? Is it appropriate? (Again, lots more to say on that another time.)
Keep fb what it was for originally: letting all your friends know what you're doing/thinking/feeling. Eliminate the "how many people are fans of my idea?" goofiness (guys like group attention) or "who responded to my post?" (girls like to be noticed personally).
Post stuff worth your friends' time, not just to say "notice me!" (Check this comedy out, on that kind of guy.)
Drop FB like a hot rock if you find yourself neglecting the people physically present with you, with whom you are covenantally bound - like say, your parents, spouse, or children.
Okay, that might qualify as rant status, but do you get my point?
I guess if you comment on this, then you're flirting... ha!
Such a connection would be the legalistic mind at work, applying things woodenly across important category lines...