I have actually reconnected with two old high school friends and one old college friend. All three were friends with whom I'd drifted apart because the thing we had in common, school, ended. All three times the results were almost identical!
We got together, we were both happy to see each other and reconnect. We chatted about what we'd been doing since the old days, where we were now, work, kids, etc. And then... well, then, we really had nothing else to talk about. There was really no common ground. The common ground that had existed years ago was gone and we might as well have been two complete strangers who decided to tell each other about our lives, past & present.
I had a really really good friend in college with whom I lost touch after I had kids. I'd really like to see her again but she lives in a different city. I looked her up and found an address for her and wrote her a letter, but I never mailed it. I knew that, especially living in different cities, the chances that we'd actually reconnect on a permanent basis are slim. Sad, I know, but there it is.
I'm not on facebook and I've had several people reason that reconnecting with long lost friends is a great reason to get on facebook. My answer is always the same. Been there, done that.
Now, I'm not saying that I wouldn't give another old friend a chance, if providence were such that I ran into someone like that again. I don't really have any hard feelings toward any of those people so why not! But after my previous experiences, I'm doubtful anything would come of it. And at this point, I probably wouldn't go very far out of my way to make it happen.
Anyway, YMMV but that was my experience.