According to the Alexa ranking system, its already at 2,508.
As far as I'm concerned, I've never seen any web site gain such immense popularity so quickly.
My question to you, is what about the site made it so popular so fast? is it repeatable? And lastly where is the business model?
Besides that, to make sure I wasn't crazy, I checked some chat logs I had. I did send some FML links to a friend on Jan 14th, so the domain was registered at least 4 days before the date mentioned. In that case, maybe it could have been simply re-registered, as sho mentioned.
The earliest post I can see, #6, has the date of 10/13/2008. That's still pretty recent, but earlier than the time in the comment. It's possible it was at a different domain, of course, or that the domain was re-registered.