Given the success of the PlayStation 4 – and, to be fair, the PlayStation 3 before it – you probably won’t be surprised to learn that the PlayStation Network is currently the largest gaming service in the world. With around 70 million monthly active users, it eclipses Steam (67 million) and Xbox Live (55 million).

There are a few wrinkles here, however. Not all of the PSN’s MAUs are paying subscribers, as PlayStation Plus had 26.4 million active members at last count. All three companies will also be measuring their users differently; does, for example, logging into your international PSN accounts once a month add a couple of extra MAU to the total? Does playing Minesweeper every now and then bump up those Xbox Live statistics?

Regardless, with subscription services like PlayStation Now and PlayStation Vue becoming increasingly important to companies like Sony, the attention placed on monthly active users is only going to increase. Why? Because every time someone logs in, they have an opportunity to sell you something, and that’s what they care about.