A new matchmaking system could mean a better connection with your brothers in arms.
There's nothing worse than playing an online game and experiencing lag between you and your fellow players. Past Call of Duty titles have relied in part on a regional matchmaking system that put a preference on grabbing teammates and opponents close to your location. Black Ops 2 will change that, relying exclusively on latency readings in the hopes of keeping lag to a minimum.
This means a couple of things; Firstly, your gameplay should, in theory, be as lag free as possible given that your connection to your fellow players is the only variable being considered when pairing you up. But it also means that your multiplayer matches could take place with people from different corners of the country, continent, or globe, so long as their connections are super speedy.
Of course, the further you are away from any given player in terms of physical location, the greater the chances that their ping will fall outside the acceptable range. In the end, you'll likely be playing the vast majority of your matches with those from your neck of the woods anyway. Though it remains to be seen just how well the new matchmaking system will perform when hit with the weight of millions of players.