Done with that Zynga story? Thought that was all the economics you were getting today? Nope. While he's not recommending investor action, writer Paul Manwaring did some number crunching and conservatively valued Team Fortress 2's unique items economy at, oh, about $50 million.
Now, that's not $50 million in real money that Valve has either made, or has been invested by gamers into a system and is floating around loose somewhere. Hats and unique items are found by unlocking crates, crates are unlocked with keys, and keys can be acquired for free, basically at the equivalence of 18 dropped weapons to one key. (They may also be bought for actual money, too.) This is a valuation, nothing more.
Manwaring examined the statistics kept (and made public) for TF2 and, long story short, finds that a community of 30,000 concurrent players each day in TF2 on Steam is injecting $1.54 million worth of "refined metal" into this virtual economy each week. Refined metal is what creates a key. Since the hat economy began in May 2009, Manwaring estimates that "we can be confident in a minimum figure of $52.7 million," as its valuation, "without even taking into account weapons bought in the store, promotional items and more. The true figure is probably double this."
I highly recommend you read Manwaring's entire post. Again, it's not money in Valve's bank account. But it is another way to characterize the enthusiasm and time investment Team Fortress 2's dedicated players sink into the game.
The $50 Million Virtual Millinery [Paul Manwaring, for The Online Society]