There’s a rumor going around today that Twitter users are starting to see ads after a brief service outage. Could it be that Twitter is finally testing a business model? Maybe. But so far, according to most in-the-know, they haven’t made a dime — apparently by design, since they’ve been exclusively focused on growing their brand and cult status.

But some popular Web 2.0 luminaries have said Twitter could be a billion dollar business just by sticking ads in in the huge volume of “tweets” that go out every day. Until now, that theory’s been untested.

Anyone who’s read any of the related posts in my blog knows where I stand. I think “audience first; monetization later” is a load of crap. I’m reminded of a famous quote, actually:

“Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it’s the only thing that ever has.”
-Margaret Mead

My version would go something like this…”Never doubt that a small group of people willing to give you their billing info can create a business. Indeed, it’s the only thing that ever has.”

For proof of my theory, I would just point to Club Penguin. Sure, it’s stylish to talk about the Bebo exit, the Last.fm windfall, etc. But Club Penguin got $700mm from Disney, a bigger exit than anything recently except YouTube to Google. Why? Because they have 650,000 people paying $6.95/month for a service that’s worth something to them.

So if anyone wants to throw down a bet with me about where Twitter will be in terms of revenue come Tax Day 2009, look at my CV for contact info and get in touch…