A large question in the video game industry right now is whether digital or retail purchases are better. While purchasing a game from the comfort of your preferred gaming machine is nice, the download times compared to retail disc install times are not. Valve is hoping to help that problem by upgrading Steam's backend code, and improving the overall download speeds for the platform. You can read the technical details of it here, but the quick summary is: faster download speeds for videos, faster download speeds for games.
Valve used this opportunity to announce that DOTA 2 (Defense of the Ancients 2) would be delivered digitally using this new code, implying that it may come soon, at least in Valve time. There have been rumors that DOTA 2 will be shown at August's Gamescom event in Germany, so information may come soon. We'll be sure to write about this new information when it is revealed, and any other updates about Defense of the Ancients 2.
Defense of the Ancients 2 is a sequel to a beloved Warcraft III mod, similar to the treatment that Valve gave Team Fortress 2, the sequel to a popular Quake mod. The concept of single, powerful units fighting each other has been borrowed from DOTA into several games, like the recent Monday Night Combat, and the PC-only multiplayer Demigod.