An anonymous reader writes "The folks at Ars Technica scraped a ton of gameplay data from Steam's player profiles to provide statistics on how many people own each game, and how often it's played. For example: 37% of the ~781 million games owned by Steam users have never been played. Dota 2 has been played by almost 26 million people for a total of 3.8 billion hours. Players of CoD: Modern Warfare 2 spend six times as long in multiplayer as in single-player. This sampling gives much more precise data than we usually have about game sales rates. 'If there's one big takeaway from looking at the entirety of our Steam sales and player data, it's that a few huge ultra-hits are driving the majority of Steam usage. The vast majority of titles form a "long tail" of relative crumbs. Out of about 2,750 titles we've tracked using our sampling method, the top 110 sellers represent about half of the individual games registered to Steam accounts. That's about four percent of the distinct titles, each of which has sold 1.38 million copies or more. This represents about 50 percent of the registered sales on the service. ... about half of the estimated 18.5 billion man-hours that have been spent across all Steam games have gone toward just the six most popular titles.'"