What do you get if you add a great big Christmas holiday to a winter sale and subtract the people too wary of Steam's recent data spillage (opens in new tab) to play any of their games over the break (that's none, by the way)? Twelve million. Twelve million has become Steam's peak concurrent user record, less than a year after it first passed nine million (opens in new tab).
It broke the record around 4:42 PM GMT on January 3—presumably as working folk scrambled to enjoy our last day off—and peaked at 12,332,000. For all that Steam has come into the firing line for its shoddy customer service (opens in new tab), dubious consumer rights interpretation (opens in new tab) and lack of quality control, the numbers say it's still providing an indispensable service.
Thanks, Gamasutra (opens in new tab).