They know how to sell their games.  They're perfect at inciting that impulse purchase by putting up a game for so cheap that even if you don't need or want it, you can't resist.  This past weekend their extremely popular survival horror FPS "Left 4 Dead" was available on Steam for 50% off.  That means you could get a couple-months old blockbuster for $25.  It  goes without saying that this is an amazing deal.

Because of this deal the sales numbers for Left 4 Dead on Steam went up 3000%.  That's not a typo, three-thousand percent.  Not only that, but the game sold so well that it actually outperformed the game at launch.  Amazing.  Hey Sony and Microsoft, you want to know how to solidify digital distribution as a means of content delivery?  Start offering up some limited-time deals to subscribers like Valve does!  The only unfortunate thing is that I already own Left 4 Dead for both the Xbox 360 and PC.  It's funny, I actually got it for PC from Steam when they dropped the price to $35 a few weeks ago...and I thought that was a smoking deal.

You can check out the article that I read about this from here: http://www.joystiq.com/2009/02/20/steams-left-4-dead-sale-increased-purchase-infection-by-3000/

Also on a related note I saw this in my twitter feed yesterday and I couldn't help but laugh: http://www.electric-escape.net/node/1426.  Props to @jcallinan for linking this up, haha!