For a very, very long time, I’ve been a subscriber to a very old-skool geek lisstserv the traditions of which prohibit me from naming. It’s been around for probably 20+ years, and I’ve been a subscriber for probably 10 years.

I have no interaction with any of the listmembers in the real world. Its geographical centers of gravity are Boston and the Bay Area, and I live in Texas. It, like the Well, is just a good place to go for profoundly intelligent conversation amongst the overeducated. It’s a good thing, if you like that sort of thing.

Anyway, comes now Facebook.

By now, all of us on these networks are unsurprised to discover online that two friends we see as belonging to unrelated social spheres are in fact connected by a third circle previously unknown to us. This is the “small world” aspect of Facebook and similar services, and it’s a big part of the appeal — you get to see your own social networks from other perspectives, so to speak, and that gives us all a little buzz. But last week something even weirder happened.

Facebook, like most such services, has a “people you might know” list. I’ve long assumed that this mostly worked off friends-list comparisons — if you were friends with Bob and Mary, and both Bob and Mary are friends with Jack, it might think that you, too, might want to be “friends” with Jack. Of course the algorithms go many more steps into the trees, and of course they’re more elaborate than this, but that’s the root of the tool, or so I assumed.

My weird event, though, suggests that something even more subtle is going on. I logged in last week to discover that Facebook was suggesting that I might want to be friends with H.M. I do not know H.M. in real life, but she is also a longtime subscriber to the listserve I mentioned above. We have no friends in common. I doubt we have friends of friends in common, but I cannot tell this. (It is possible, I suppose, that Facebook has found some way to convince Safari — my “disposable” browser, which I fully reset every time I run it for privacy reasons — to allow its scripts to sniff the addresses in Mail.app, but this seems unlikely (more unlikely, though, is that such a thing is possible AND that I’d be unaware of it)). I’d very much like to know how Facebook determined that H.M. is someone I might now, but unlike (e.g.) LinkedIn, FB does not disclose how many steps away a person is.

The whole thing reminds me of something my friend Laura said to me a while back: “We have only begun to realize the degree to which the Internet, via Google, is going to radically change  the way we work with information.” We were discussing social recommendation services like LibraryThing, but this H.M./Facebook development suggests that our social networks themselves — the real ones, not the shadows on the cave wall given us by Facebook — are the real places we’ll see weird developments.