Since launching its own digital distribution service with Steam back in 2003, Valve has retained the exclusive rights to selling its games digitally.

Today that changes, however, as Valve is for the first time ever allowing another digital distributor to sell its titles. Gamespot’s Impulse is the lucky proprietor that may now sell the likes of Half Life, Team Fortress, and many more to come.

Incidentally, Impulse is also the most annoying digital distributor in the world to anyone who doesn’t live in the USA, due to the fact that most of their games are only available in that region.

Impulse has been running since June 2008, and was purchased by Gamestop in March 2011. While it has managed to gain a slight foothold in the digital distribution space, it does not come close to competing with Steam in terms of sheer sales volumes.

Even when bought from another retailer, Valve’s games still require you to register them on Steam, which kind of defeats the point of buying them from another retailer.