Steam has surpassed 125 million active users and is home to more than 4,500 games, Valve has announced.
The firm also revealed that 400m pieces of user-generated content had been created for games on its store.
The figure is a dramatic rise from the 100m users announced in September 2014, meaning the digital store has been picking up some 5m users each month.
Fresh figures from the Steam stats page also show the number hit a new peak record on Sunday, reaching 8.935,330 concurrent users.
Valve will be at GDC next month to unveil the latest Steam Machines and controller design, and is also set to reveal its virtual reality headset.