One drawback with purchasing a digital copy of a game is that there's nothing to do with it when you're tired of playing. Valve's new program, Steam Gifts, doesn't solve that problem, but it is a step towards letting players to get rid of unwanted games — which is a step in the right direction. The beta version of the program (which can be activated in your Steam account settings) allows players to barter in-game items and games that have been gifted to them.
You won't be able to trade a digital copy of a game you've already played, but if someone were to send you copy of Limbo over Steam and — for whatever reason — you don't want it, as long as you don't open the gifted game and add it to your game library, it can be traded with other beta participants. Whoever you trade the game to is then free to add the game to his or her library or to trade it again for something better.
There are also in-game items that have become trade-able through the Steam Gifts infrastructure. So far, only Team Fortress 2 items have been implemented, but Steam has said it's working with third-party developers to incorporate more games over the next few months and it expects to have Portal 2 items for trade in the near future.
Aug 10, 2011