It is because you are brand new. The good folks at MMO Champion don't want someone to be able to create/authenticate a new account and then immediately flood the boards with advertisements or other similarly terrible threads.
If a post says it needs to be approved, that means it's been caught by our spam filter. It's a necessary inconvenience, because it lets us take care of gold sellers and the like.
We go through and empty it out pretty frequently, so you should see your post soon!