The co-owner of widely used computer gaming service ESEA has admitted that the company used its client software to mine bitcoins using customers hardware without their knowledge. Some ESEA users say that the unannounced activity overheated their graphics cards, damaging them in the process.ESEA is a paid subscription service that offers competitive matchmaking, league play and cheat prevention to an advertised 14,000+ membership for about $7 per month. It supports mostly games popular on the competitive scene, including Team Fortress 2, League of Legends and Starcraft 2. ESEAs subscription services are delivered via locally installed client software, which acts as a server browser and social venue, in addition to providing anti-cheat functionality.[MORE PRIVACY: EFF: Trust Twitter -- but not Apple or Verizon -- to protect your privacy]ESEA user Unisolz said in a forum thread posted early Wednesday that an examination of the client revealed the presence of OpenCL miner a piece of software that uses graphics processors to perform the strenuous calculations involved in Bitcoin mining.The revelation prompted widespread condemnation on ESEAs official forums, which had already seen a number of recent posts from users complaining about antivirus warnings and overheating hardware. The discussion quickly spread to other sites, notably Reddit, where user renalucario collected screenshots and other relevant information - including official forum posts from ESEA co-owner Eric Thunberg admitting that bitcoin mining took place.Thunberg posting under the screen name lpkane said initially that the unannounced inclusion of a bitcoin miner in the ESEA client was considered as an april fools, and that a technical error resulted in it being deployed across the service two days ago, resulting in a total of two bitcoins (about $280) being mined.For the record, I told [client creator] jag[uar] he shouldnt be lazy and run the miner in a separate process, rookie move, he joked.In a subsequent posting, however, Thunberg admitted that the process had been happening for two weeks, not two days, and that the take had been nearly 30 bitcoins (more than $3,600), rather than just two. He said that the funds would be donated to a tournament prize pool and that all current premium users would get a free month of service.This is way more shady than I originally thought, and as the person who is ultimately responsible for everything its 100% my fault, Thunberg wrote.Thunberg declined to comment when contacted by Network World, but ESEA co-owner Craig Levine said that he had no knowledge of any bitcoin mining until the scandal broke.I am in the process of fully investigating the extent of the actions and how it happened so that we take the appropriate measures to rectify the situation and put the proper safeguards in place to prevent it from reoccurring, he said, adding that a formal response would be forthcoming today.Levine did confirm that ESEA will be setting up a mechanism to handle user claims of hardware damage.Email Jon Gold at email@example.com and follow him on Twitter at @NWWJonGold.Read more about wide area network in Network World's Wide Area Network section.