This is a tool that gamers can use to make their own missions along with races and creations can then be shared on the Social Club of Rockstar. Others can then go ahead and play them.
There is nothing wrong with this concept, but it has been said that it could mean more glitches, bugs and possibly cheaters. On the plus side the Content Creator is free and it is new.
Gamers are still waiting to get their hands on the heists for GTA Online, Rockstar have said that they will be here sometime this year.