Along with the new Trading Card feature, Valve has added a host of changes to the way Steam profiles are displayed along the addition of a ‘Steam Level’ to user accounts.
The move comes at a time when console gaming is stealing all the headlines, see PS4's E3 dominance and Microsoft's Xbox One backtracking as examples, but Steam, exclusively for PC, is quietly plodding away in the background (perhaps readying Half-Life 3).
Once collected, the cards can be used to craft badges to display on your account, which can earn you unique emoticons, custom backgrounds, and even store discount coupons. And games.
Of course the cards can be traded with friends if you feel like helping them complete their collection.
Check out Steam's current list of compatible games along with an FAQ here.