What is a reputation system in a fourm? I can see that this forum has one. Does anyone know?

It is a system that will make people make better post i think

I have notices that too. I agree with paguh. I have also seen this reputation system.

When it gets set up i think that it will really improve the quality of posting.

It is set up on this forum. If you notice on all posts, there's a little green (or red!) block. That's the user's reputation. If you like what the user has posted, you can add to their reputation. If you don't like what they've said, you can subtract from their reputation, In either case, there's a little scale, right next to the post number. If you click on that you'll get another page that has the option to either agree or disagree with the post.

See the attached images. The first shows the current rep, the second shows the button to click to add/subtract rep.

Attached Images