I use Steam all the time.
Below is copied from wikipedia:
As of September 2015, over 6,400 games are available through Steam, including over 2,300 for OS X and 1,500 for Linux.[10] The service has over 125 million active[a] users.[12] Steam has had as many as 12.5 million concurrent users as of November 2015.[13] The Steam platform is considered to be the largest digital distribution platform for PC gaming; in November 2009, Stardock estimated it at 70%[14] and then later, in October 2013, it was estimated by Screen Digest that 75% of games bought online are downloaded through Steam.[15] In 2015, users purchased titles through Steam or through Steam keys from third-party vendors totaling around $3.5 billion representing 15% of the global PC game sales for the year, based on estimations made by the tracking website Steam Spy.[16][17] The success of the Steam platform has led to the development of a line of Steam Machine micro-consoles and personal computers meeting minimum specifications, and SteamOS, a Linux-based operating system built around the Steam client.