well i always watch my dragonball z gt episodes on a rlly good web site but now they show dragon ball kai, what is it?

As far as i know. Dragonball Kai is something of a remake of the dragonball series. They have shortened certain sagas,taken out the filler parts and probably worked harder on the animations to improve the episode quality. One example is the vegeta saga, where they shortened the amount of episodes that it took Goku to reach king kai's planet, to just two episodes.......i think!