As odd as it sounds, one thing that has been largely absent for a long time with PC games is a system to let players interact with one another during a game, when neither of them are playing the same game. Even though chat services and some community programs exist, few are in actual use and even fewer are practical. Using more established services like Skype or Windows Live aren't the greatest solution either, as alt-tabbing out of a game, then back again are something most computers take a long time to do, much less the fact that you're out of the game this entire time. In fact the closest comparison would be Steam, however services like Xbox Live are far easier to use, integrate with all their games and give players easy access to their friends within any game, even letting them live chat with voice in a group while none of them play the same game. Blizzard's Battle.net 2.0 looks to make a respectable start on giving PC gamers the whole package as far as their own games are concerned.
One thing consoles seem to do very well is match up players with similar skills with one another, but there is little organization after that. Battle.net will feature a very in-depth matchmaking service complete with leagues and divisions suited to player skill. One problem that plagues many PC games is that the skill divide between veteran and new players is extremely high, and finding a game with a player of similar ability can be frustrating when you get stomped every game. Likewise, when you constantly destroy your opponent with no real test of skill, the game can get boring very quickly. Ideally you're going to get better over time, so once you're placed into the appropriate division, the system can track your progress and move you up (or down) in the rankings based on your performance.
The emphasis here is definitely in the competitive gaming sector, but it has many uses for gamers who prefer single-player, those looking to play custom games, or those who just want to play with their friends. Much like Steam, Battle.net has features allowing players to save their files and savegames to a central server, making cross-computer play much easier than before. For StarCraft II, Blizzard is introducing a host of new, casual-friendly game modes for players to practice on, without having to worry about their performance. Another feature to be added is the chat system. It will integrate friends lists, messages, matchmaking, as well as a player's real friends, functioning much like the current setup most consoles use today, or that of Steam.
While Battle.net 2.0 will only work with Blizzard games, each franchise has an enormous following and each game is considered a staple in the PC gaming community. This is where Battle.net can really make an impact. Letting PC gamers connect to one another and have a community within each game instead of only outside of it really gives each player a sense of rank and purpose. Considering the combined player base in Blizzard's games alone, (including what seems to be the entire country of South Korea) banding every player on a single platform together only makes sense, especially seeing the ever-growing gap between console and PC gamers.