Presumably, content creators work out the details of that revenue split when they give their payment information to Valve, at which point they can choose to set prices for their mods or allow their patrons to pay what they want. New supplemental terms for the Steam Workshop legal agreement state that 'the percentage of Adjusted Gross Revenue that are entitled to receive will be determined by the developer/publisher of the Application' for which they've created content.

People who sell Skyrim content on the Workshop get a 25 percent cut of the revenue, but it seems that the amount a content creator receive is ultimately up to a game's publisher or developer. Update: A Valve representative responded to Gamasutra's request for clarification on revenue splits by highlighting the Skyrim Steam Workshop page, which notes that all revenue from sales of Skyrim Steam Workshop content will be split between Valve, Bethesda and the content creator(s). This opens up more avenues for budding and established game developers to get paid for their work - as former SimCity artist Bryan Shannon is by creating Cities: Skylines mods - and furthers Valve's long-stated aims of democratizing content creation for games on its platform.

Workshop mods without game