UPDATE: Valve has issued Eurogamer with a statement disputing the European Commission's claims and vowing to appeal.
A Valve spokesperson told Eurogamer: "During the seven year investigation, Valve cooperated extensively with the European Commission ("EC"), providing evidence and information as requested. However, Valve declined to admit that it broke the law, as the EC demanded. Valve disagrees with the EC findings and the fine levied against Valve.
"The EC's charges do not relate to the sale of PC games on Steam - Valve's PC gaming service. Instead the EC alleges that Valve enabled geo-blocking by providing Steam activation keys and - upon the publishers' request - locking those keys to particular territories ("region locks") within the EEA. Such keys allow a customer to activate and play a game on Steam when the user has purchased it from a third-party reseller. Valve provides Steam activation keys free of charge and does not receive any share of the purchase price when a game is sold by third-party resellers (such as a retailer or other online store).