Team Fortress 2 switched from a paid game, first seen in The Orange Box bundle, to a free-to-play title. Financially, you could say that it was supported by tips… … tips of the hat. Some responded with a wag of their finger, but others with a swipe of their credit card. Where was I going with this? Oh right. This game put Valve on the path of microtransactions, which fuels games like DOTA 2 that aren't supported in any other way.
Each of these item payments are done in game however, even Valve games, except for one. Rust has been chosen to introduce Item Stores on Steam. If you go to Rust's store page, you will see a category called “Items available for this game”. Clicking on it brings you to “Rust Item Store”, where you can buy in-game clothing, weapons, and sleeping bags with real money. This feature is not even available on Team Fortress 2 or DOTA 2.
While there has been some parallels drawn between this and the backtracked paid mods initiative, I don't see it. This is not attempting to take third-party content, some of which was plagiarized from free, existing mods, and sell it. This is an attempt to provide a platform for in-game purchases that already exist. If there's a story, I'd say it's how the initiative launched with a third-party game, and not one of Valve's two, popular, free-to-play titles.