A game in OB is a game in an Open Beta. The open beta feature means that you can sign up for an account and help test the game, for it isn't out yet. It also means that it has a lot of bugs yet to be fixed, and that is how you can help the game developers, telling them where these bugs are. A game in CB is a game in a Closed Beta. The closed beta feature means that you may sign up for an account to test it, but only some chosen folk will be able to test it. Usually, the chosen users are those who live nearer to the server base, so that internet conection problems won't happen a lot. Also, an user who've been testing games for a long time are also a choice, because the developers want people with a bit of experience doing the closed betas. Some times, you can have closed beta keys from promotions in mmosite and another sites. After the closed beta, the characters created are wiped out, so it can start all over again in an open beta. In the closed beta there are huge bugs, and a lot need to be fixed, so your job as a closed beta tester is just like in the open beta, but easier (because bugs are more easily found).