PC Games N report that Valve's Steam service has reached 50 million users with 5 million playing concurrently.
An incredible feat, and one that illustrates Steam's position in the digital marketplace.
Currently, Steam is having its annual Thanksgiving sale and among today's offers are Xcom: Enemy Unknown (-33%), Magic the Gathering: Duels of the Planeswalkers 2013 (-50%), The Walking Dead (-50%), Darksiders II (-66%), Age of Empires III Complete Edition (-75%), and Terraria (-66%).
There are also a bunch of flash sales popping up that you should keep an eye on (Dear Esther is ridiculously cheap at the time of writing this).