Six degrees of separation? That theory is long dead. As we mark the 12th (!) birthday of the social network that rules too many of our lives, Facebook tells us that with each passing year and each new "friend" we add, the connections between us and everyone else on earth (who's on Facebook) get greater, and our degrees of separation get fewer. ABC News marks the anniversary with the latest figure from Facebook: 3.57 degrees. That's how separated the site's 1.6 billion users are now, from that girl you know from high school who is still in touch with absolutely everyone from high school, to your grandfather who only has six friends who are all relatives, to the guy you met at the bar last week who friended you while you were still mid-conversation and who turns out to have nearly the top limit of 5,000 friends.

Show of hands of everyone who joined Facebook in 2004? There won't be too many since Thefacebook that Mark Zuckerberg first launched in his dorm room the night of February 4, 2004 was limited only to Harvard students.

But even in its first hours the thing was stupidly popular — as Zuckerberg's then roommate Dustin Moscovitz has said, they emailed the link to the 300-person mailing list of their dorm, Kirkland House, and "within twenty-four hours, we had somewhere between twelve hundred and fifteen hundred registrants."

Within that first year, the site quickly opened up to students at Stanford, Columbia, and Yale, followed by all the Ivy League and Boston-area schools — but unless you were a connected college student at the time, you might not have joined for a couple of years. I didn't join the thing until early 2007, and at the time it seemed dumb and less useful than Friendster, but now I sound old.

Speaking of old, the Library of Congress just tweeted this prescient, very early mention of Facebook, from 1901.

Today, Facebook is celebrating with a new feature called Friends Day, which shows you a little animated collection of snapshots from your albums. And, unlike some previous debacles when people have been shown pictures of their exes and dead children set to happy music, this feature allows you to edit the exes out of your slideshow, and hand-pick all the photos.

Zuck is sounding typically nerdy-cheery about it all saying, "That's what humanity is. People who have different interests and come together to accomplish these crazy and amazing things... that's the whole point of Friends Day."

The most interesting thing, though, is that our degrees of separation are shrinking, and we're now almost a fifth of a degree less separate from every other user than in 2011, when Facebook had about half as many users — 3.57 degrees down from 3.74.

Previously: Facebook Will Now Stop Showing You Photos Of Your Exes And Dead Pets, If You Tell It Not To