Sometime a little after 5pm EST on Dec 7, 2010, Wikileaks gained its 1 millionth Facebook fan. That’s about 10 hours after my prediction, as the growth rate slowed through the night (duh) and didn’t return to the previous day’s pace during most of the day.

Here’s the chart, showing Facebook likes (fans) in blue and Twitter followers in red. The gaps in the lines are gaps in data sampling. I sampled every 5 minutes.

Notice the funky little blip in the blue line right around the 1 million mark? Here’s another chart that zooms in on that timeframe within the red circle:

A significant acceleration starts around 1710 EST. During this period the average number of new likes per minute (LPM, it’s the new RPM) goes from 89 or so up to a peak of 516, and then decelerates back down to 83 LPM at 1800 EST, followed by a continuing decline from there onwards.

At first I thought the lift was tied solely to prime time East coast US and Canada news., i.e. people might have logged on to Facebook immediately after hearing news stories about Wikileaks. That probably happened, to some degree. But if that were the only factor, we should have expected a similar bump, or sustained high growth, through the 1800-1900 hour, which is also news-heavy. And that’s not the case, as you can plainly see.

My best guess is that a crowd of people were aware the Wikileaks Facebook page was almost at 1M fans, and they all piled on when it got close to push Wikileaks over the 1M mark. Probably some of them hoped to be the 1 millionth fan. (Is there a badge for that?)

In case you’re interested, below is the raw data for 1500 EST to 2000 EST. Note I’ve calculated average new likes per minute, as I’m sampling every 5 minutes.

Why bother with all this analysis? Ethics and aims of Wikileaks aside, I just think this an interesting phenomenon at the intersection of math, psychology, and social networks. It’s not often you get to watch a meme go viral, in realtime, with accurate metrics available for tracking it. Lucky us.

I’ll keep my samples running for a while, in case anything else interesting happens.