How do you encourage and reward players for spending more time playing games on Steam? That’s a question Valve has been asking internally, and the solution is apparently to create a trading card game that rewards the player the more they play and interact.Valve has today introduced Steam Trading Cards into beta. It involves the collection of virtual cards that can be earned in part by playing your favorite games. Once collected, those cards can be turned into game badges, or you can trade them on Steam as a community item.Collecting the cards isn’t just about playing a game, though. You can only collect up to half of the cards associated with each game that way. The rest need to be collected through trading, which brings with it a major community participation element to the system. For example, taking part in beta group discussions, trade discussions, or bartering with friends can all net you new cards.Valve has also been clever with how the cards can be used. Only once you’ve collected a complete set of cards can you turn them into game badges that become linked with your account. But that crafting exercise also earns each player a number of items such as profile backgrounds, emoticons, even coupons and game DLC.To complete the system, Valve has also introduced XP that’s associated with each badge. The more badges you collect, the higher your XP and the higher your overall Steam Level and profile customization options. That level and XP will be publicly viewable to other Steam users, meaning there’s going to be some serious competition to level up and be proclaimed number one Steam gamer.Steam Trading Cards are sure to be popular and this is a clever move by Valve. It takes the relatively mundane practice of managing a Steam account and adds elements of gaming and competition to it. For the beta, the number of participating games is quite limited and includes:Counter-Strike: Global OffensiveDon’t Starve Dota 2Half-Life 2Portal 2Team Fortress 2That’s sure to increase pretty quickly, and I doubt it will be long before every major release includes Steam Trading Cards support as a standard feature.