Steam’s found a new way to get people who don’t really like to play games, to play games. Currently in beta, certain games will now award you “trading cards” whilst playing, that you can then, uh, trade with others to make a set. Make a set and you can “craft badges”. Craft a badge, and you’re awarded with achievement paraphernalia like emoticons to use in chat, profile backgrounds, and even discounts (presumably for Half-Life 2). All of which are tradable.
And if that wasn’t meta enough for you, your Steam profile itself can earn XP and level up:
All badges now have XP which contributes to your Steam Level, a summary of your badge collection. You can view someone’s Steam Level by hovering over their avatar. Leveling up earns you non-tradable items like profile showcases, extra friends list slots, and more.
Those who are interested to join the beta need only to level up their clicking skills and join this Steam group. Games supported right now are Portal 2, Team Fortress 2, Counterstrike Global Offense, Half-Life 2 and the as-yet-unreleased (but marvellous) Don’t Starve.