This, exactly. My HS best friend and I remained best friends for about five years after I graduated high school. (She’s a couple years older than me, so obviously it had been longer since she graduated high school.) I dumped her as a friend for being incredibly self-centered and narcissistic and after that, I wasn’t in touch with anyone from high school until Facebook came around.
Five that I have regular contact with (email) and see when I am near where they live. A whole pile of others who get together for various things. A couple of years ago all my football team got together to meet up with our former coach who was dying of cancer. A few months ago one of the guys sent out a general invitation to a housewarming he was having at an old, former gold rush brothel he had bought. About 15 people turned up for the day. I finished high school nearly 40 years ago.
None regularly. There are a couple whom I come across very occasionally, simply because we’re members of the same organisations.
My best friend from high school and I are still best friends (25 years of friendship). Aside from her, and discounting Facebook, I was regularly in touch with 3 others. Coming from a fairly small town, and having my parents still live in the community, I am constantly hearing, “Remember so-and-so? I saw her mom the other day” types of things.
When I lived within an hour of where I grew up, I actually worked with a couple of my HS classmates. After I moved 400 miles away, I would run into a few of the nearly 600 people that I graduated with when visiting my parents.
A few years ago, I connected with a classmate from kindergarten through HS on a genealogy website. He helped me with researching some of my family. Come to find out, I’m a distant cousin of his wife.
Since the advent of Facebook, I’ve reconnected with about fifteen of them, including my HS best friend. She and I had dinner the last time that I visited up north. She’ll be in my area on business next month and we plan on getting together again.
I’ve also friended or been friended by five of my classmates who live within an hour of me. The wife of one of them works for the same company that I do. I’ve run into another over the years (I ran into her pre-FB) dabbling in the music business - we’ve actually done work on a couple of projects together. I recently ate in another’s restaurant about an hour from my house.
I graduated in 1981, so there will be a reunion next year. I’m seriously considering going; I think that the statute of limitations is up by now. 
Eight. We go to the same uni.
I don’t keep in contact with anyone I went to high school with - I was never close with any of my friends there. I did make some friends in my last year of high school (we met on the set of a TV quiz show for students) that I am still close friends with to this day.
I attended 2 different high schools, so once or twice I’ve gone to 2 different high school reunions a month or 2 apart. I graduated high school in 1974, and went to a 35th reunion last year. It’s probably my last one. I stay in semi-contact with 2 people from that class of about 100 people, mostly by e-mail. I might see them face to face every other year or so. The rest of the ones that were at the reunion were strangers who just happened to have the same name as some people I once knew. There was one guy that I hung out with there, though, who simply dropped off the face of the earth. He moved one day, and nobody ever heard from him again. Not his family, his friends, nobody. Too bad - I enjoyed hanging out with Larry.
From the other school, it’s more or less the same story. There are a few that I get e-mail from once in awhile. One was a pothead in high school who has become a member of the Tea Party, I think. He forwards every conservative-slanted e-mail that’s circulating to everyone in his address book, even when a basic check of Snopes will show him it’s false. He’s a nice guy in person, though, so his stuff usually goes into the bit-bucket.
Lessee- I can think of…
three at church
one in Los Angeles where my brother lives
about 40 via Facebook, seeing around town occasionally & having friendly chats with but don’t actually buddy around with, & about a dozen of them who I might make plans to hang with at times.
Can’t think of anyone apart from the odd update on Facebook.
I have friends from that time who were at different schools who I’m still in touch with, but no-one I actually took classes with.
None. It was a small school, and most of my friendships were based on less criteria than can really be sustained long-term. Fine for a few years, but we grew apart rapidly, and now I have no idea what they’re all doing.
I am barely in touch with anybody at all, currently, which is strangely satisfying.
None, I didn’t even keep up with them when I was in high school.
ETA: Graduated 1976.
None. I moved, life goes on, etc. I had quite a few friends, but I guess we weren’t really that close.
I was homeschooled for most of my high school career, but I’m still in touch with about six friends from around that time–two of them quite often.
10 or so through facebook. 5 or so that I kept up with over the years.
About the same numbers for college friends.
I’m 35.
Zero. I’m Facebook friends with one of my Debate teachers, as well as a few college friends, but zero high school friends.
Joe
Graduated 1995. Aside from people I work with, I actually know very few people I didn’t know in high school (though we didn’t all go to the same school). The vast majority of people I hung out with in high school didn’t move away, and I’m still in touch with the ones who did.
I’m 25 and live about a half mile from my high school, so I see old classmates around the neighborhood all the time (I work service jobs locally, so I serve them drinks etc too). More so than ever the last two years as everyone is graduating from college and moving back in with their parents. I’m also Facebook friends with a ton of people from high school but never talk to them.
I’m still fairly good friends with about 9 people who attended my high school, and I often see their friends who went there as well - but I barely count them as ‘from high school’ because I didn’t ever see any of them at school (most were in the accelerated track while I was in the remedial, for one). I became good friends with two kids who lived in my neighborhood outside of school, and they both introduced me to all their friends, who I became good friends with as well. I think I had one class with one of the friends I stay in touch with, but it was before we were friends.
I didn’t graduate high school so I don’t think I will even be invited to high school reunions. No interest in going anyway.
I’m still in phone contact with 20 people from high school nine years out. I randomly hangout with another 20 or so and probably another 15 that I know what’s going on in their life through the gossip chain. I’m hooked up with most of the rest of them through Facebook but mostly that is just me stalking them or occasionally I’ll get comments about things I’ve done.
From high school - about seven through facebook, 2-3 face to face, and that’s only when I’m visiting my hometown and happen to run into them. I was far from popular in high school and have a lousy memory when it comes to that time in my life. I’ve forgotten names and faces of a lot of classmates on purpose and usually don’t recognize them when I do bump into them. They always seem to remember me, though. Figures. Oddly enough, my class was fairly large but nobody has ever organized a reunion. Like rhubarbarin I didn’t graduate either but I probably would have gone if one was ever held, just for the yuks.