ComScore said that the highly variable growth rates in the final two weeks (extremely high in the penultimate week and extremely low in the final week) are primarily a function of the way the calendar fell in relation to Christmas.

FORBES: U.S. Online Holiday Spending Up 14% To $42.3 Billion; 'Fiscal Cliff' Debate Stalled Additional Growth

The other key variable is the growth in game streaming through services such as TwitchTV and own3d.tv.

FORBES: With StarCraft II Declining, The World's Top PC Game League Of Legends Sees Continued Growth

This is because the rate of economic growth is the only variable that really matters when it comes to federal finances.

FORBES: Before Going Over The Fiscal Cliff, Let The Markets Score The Competing Tax Plans