If you look under your profile picture where the info is at, you will now see 2 new bars: a "Points" bar and a "Reputation" bar.
Points
Points are gained by just being active around the forum, different post are worth different points. The member with the most points on the first of every month will be titled as "Most active user of the month". More prises may come later.
Reputation
Rep is gained by votes by your fellow member's. As you can see now on every post in the upper right hand corner there is a +/- button. If you press + it gains a rep point for that person, while - subtracts a point. The member with the most rep on the first of every month will be titled "Most popular user of the month". More prises may come later.