Steam Cards: How Do They Work? @ Techgage
 

When Valve introduced its trading cards mechanic on Steam this past May, I wasn't sure what to expect, or sure if anyone would care. After the recent summer sale wrapped-up, though, I realized that you should never underestimate Valve. For better or for worse, trading cards are intriguing, so we're taking a look at how it all works.

http://techgage.com/article/steam-ca...-do-they-work/