Update 10/02/2025: As noted by SteamDB on Bluesky, while this specific page on Steam's advertising policy is new, the policy itself is not. Valve has had a ban on these kinds of in-game ads in Steam games for the last five years at minimum, viewable on its pricing policy page.Original story: First reported by Gaming on Linux, Valve has added a new advertising page to its Steamworks developer documentation. The page outlines what kinds of advertising and promotion it will allow on Steam, while ex...