family....yes and no.  I'm not romantically/emotionally interested in chics, nor have I ever been, so I don't really see any benefit to me or my parents in sharing that I've enjoyed both guys and chics sexually.  They've known I'm "gay" for about 8 yrs now.  I have told my sister I'm bi.  Its just me and her and she's bi, too.  Dad doesn't know about her being bi, tho.  She dated guys all along, got married and had a kid so the obvious assumption is being straight.  I might tell others in my family about liking girls, but it would just be if it was relevant to something.  Since I don't really date or meet chics it rarely comes up in casual conversation.
A friend of any value I'd tell I'm bi, although gay friends, especially casual ones, can be really annoying when they ascribe lifestyles to orientation.  Actually, I don't really live a gay lifestyle, let alone a bi one.
I've never had a gf, and I didn't know that I like girls with my first bf.  It was while I was with him that I found out.  He and I actually fucked one of his girlfriends from high school.  They were really close friends but never had sex.  His first time with a girl was actually mine as well.  We don't talk anymore so I don't really know what he thinks about his orientation.  He seemed to enjoy it at the time but as far as I know he didn't spend anytime chasing girls after that 3-way or after we broke-up.  My 2nd LTR was with a guy and he was bi and had spent a lot more time having sex with girls than I had, or have, for that matter.  In the case of my first bf and the 2nd, we spent a lot more time chasing other boys than girls.  lol
I've only had other lovers with my bf's (3-ways), but I don't recall which ones knew I liked girls and which ones didn't.  The girl knew and perhaps was excited to be our first girl and I think it was her first gay/bi men, esp bi 3-way, but I don't remember if she had done 3-ways before.  She had a bf at the time and he was REALLY hot, but, as far as she knew, he wasn't interested in a 4-way, or even any guy, for that matter.  At the time I was quite turned on by the notion of fucking his girlfriend, among other things.  I wonder if he ever found out.
Work people and friends have always known I'm gay until I got a blue-collar, union job where they all assume I'm straight.  Back in the closet and I don't like it at all.  We talk about sex all the time and I bring in my Playboy's (subscription rates are very cheap, btw) and porn DVD's.  We watch them on my laptop.  Black Pipe Layer's 4 is one of my faves and they seemed to like it, too.  Hmm, wonder why?  lol  It is kinda fun how I can get away with grabbing their asses, tho.  I only pick on my favorites.  

  On days there's this cute little redhead with the sweetest personality...prolly 5'8", 160lbs, smiles a lot.  On nights my boy is a big one...prolly 6'2" 220lbs, dark brown & brown...used to play football so he's still got the big arms & chest.  We get along really, really well mentally.  We're each very good and quick to expect what the other is going to do, which is nice when you've got to work so closely with someone in a dangerous environment.  I think both guys are 25 or so.
God, its been so long since I've been with a bf or on a date out in public its hard to answer.  I really think having to go back into the closet at work has made me over-all a lot more constrained and feeling less open about my life and feelings.  In times past it has been much more of a function of where I happened to be.  There's certain locales where you don't want to appear openly gay/bi or you'll be beat down or robbed or whatever.  Other places people just might stare and in a lot of places people will just ignore you like they do everyone else.  lol