Rimworld was recently released on Steam Early Access. For those not aware, Rimworld is a bit like Dwarf Fortress but with a sci-fi twist. It's a game that tasks you with surviving on an alien planet after you crash land, building up a colony and eventually, if you so desire, escaping.

Ludeon Studios was selling a DRM-free version on their site for quite some time now prior to its arrival on Early Access. The studio decided to reward those who supported them directly by giving everyone a free Steam key. However, because people are jerks, a number of fraudulent purchases were made resulting in free Steam keys given and thousands of dollars worth of chargebacks. It is because of this that Ludeon Studios will no longer give out free Steam keys to those that purchase directly through their site.
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Ludeon says that everyone that bought the game prior to July 17 will still get their Steam key if they want.