Reputation points show who has been helpful to other users.
How to get reputation
To get reputation, you must post something to answer another's question, or is useful. If a member believes it is helpful, they can press the '+' button in the top right corner of the message. If the user thinks the post is unkind or insulting, press the '-' button to take away reputation.
The 'thanks' button
The thanks button can be used if you think something was particularly helpful, useful, or answered a question you had. It adds 2 reputation points, while normal '+' button gives only 1.

I gave ya first Rep!!! Woo!

Ah cool! I gave rgangsta's 1st! Now give me one!

Why did you - one?

I fear that people may abuse this system...

Fine Sorry!

Oh, I wasn't talking about you. I didn't "-" your post.

Oh, okay, then who did?????????

I did.

Why?

Probably because you asked for one, but you didn't specify + or -!!! loophole FTW

Ahhhh, okay! Can you give me a "+" one, just to give me a break.

I did it because you asked. If you read it over, you'd realize that isn't the point of the system.

I just gave you one at the top.