I've come to really appreciate how well my bro and I get along. When we were little we fought, and even into high school we had our spats over use of the car or whatever, but by then we had friends and social activities in common (we're a year and a half apart in age). Now we share a lot of friends, and although he's different in some ways (doesn't read that much, probably isn't quite as political as I am, is a geologist) we have enough in common that when we visit it's yak yak yak yak. As Lee can attest.

But then, he has tons of friends in general -- and friendly friends, at that. I feel like I'm losing mine. A couple of once-close friends are now more distant (though we're still on friendly terms) for reasons I don't fully understand, and others are perfectly friendly but have become more of homebodies. That and my relative isolation at work have made me feel really lonely at times when the kids are away at school. And soon they'll be away-away -- and both swear they will not be living in Minnesota.
That's the main reason (that and the climate) that I keep thinking of moving to Denver. I'd know Lee, my brother, and a couple of other people, and hopefully I could meet their friends, who seem a bit more active and outgoing than my own.
I interact with a lot of people on FB whom I've never met in person. Or, in some cases, just met once. I got one of my part-time jobs thanks to a referral by a woman I'm friends with on FB (we have mutual friends) but have never met in person.
Then there's you guys!

! As on FB, I haven't met you all in person, but one of you I'm hoping to meet in a couple of weeks!
