A month or two ago, it was “received wisdom” that Facebook was the nbt (Next Big Thing) and it seemed so when Microsoft’s Steve Balmer donned a white beard, dressed up in a red suit, started muttering “Yo Ho Ho” and casually dropped $240 million down Facebook’s chimney. It wasn’t even Christmas.

I remember having doubts about the $15 billion valuation at the time (see Is Facebook Worth $15bn?). Now I have even bigger doubts. I overheard the following snippet:

“I’m outa Facebook. My mom was all over it, trying to work out who I’m dating – and trying to teach the Peppermint Twist to someone she used to work with, like in nineteen-before-the-Berlin-Wall-fell-down. I’m on Hi5 and I’ve sent you an invite.”

Some commentators are suggesting that Facebook is getting too intrusive with its ads and the specter of “big brother” is casting a shadow – but maybe it’s not “big brother”, but “my mother” that’s got the teens running scared and, apparently, emigrating to new social networking sites. It conjures up the amusing vision of the baby boomers chasing their gen-x and gen-y kids through Internet, leaving ghost web sites and bewildered entrepreneurs in their wake.

I’m not so sure that the Facebook idea is particularly sticky anyway. If it was, MySpace would have been sticky too and Facebook would be nowhere. What Facebook did that was different was open its interface to allow plug-ins and mash-ups to be added. And right now everyone is suddenly doing that. Monkey see, monkey do. When Google offered up a common standard for it, Facebook ceased to be the tar-baby it was believed to be.

Internet users of all ages are used to setting up new email ID’s, chat IDs, ego web sites, Digg identities and so on. They’re all so disposable. If you get sick of your Second Life avatar, well walk away and it’s dead. It cannot lock you in.

So what did Steve-Father-Xmas-Ballmer say, a few days before he paid a visit to Facebook with a bag full of cash? He said, “Sites such as Geocities had most of what Facebook has.”

Well said, Steve.

You remember Geocities, surely. Yahoo! paid $3 billion for it in 1999. It had millions of users and now it has about, er, a handful, maybe. Is Facebook the next Geocities?