What are these points?

If you save up 1,000,000 points you can change them in for an official yahoo attaboy.

The link to the points/scoring info is below. My guess is you already know how the site works. There is a leaderboard because Yahoo/Verizon hasn't removed it yet.

points when you reach a certain amount gets you to the next level as you level up you can contribute more to the site each levels has restrictions on what you can and can not do such as how many questions you can ask and answer points have no money value towards them and there are no actual prizes learn more about points and levels here http://answers.yahoo.com/info/scoring_system 

You earn points by participating in the YA community. The more points you have, the more questions and answers you can ask and answer per Yahoo "day." The Yahoo "day" does NOT end or start at midnight or 2400 military time in YOUR time zone. 

At one time, Yahoo did have contests and the prizes were merchandise with Yahoo and YA logos. Those contests stopped in 2014. Since Verizon has owned Yahoo for well over 3 years, there have been No contests.

If the only reason you are on YA is to annoy, lecture or provoke people or advertise something, please leave. The last thing we want is another ranting point gamer. Go to Reddit. 

no, you cant buy anything with those points, the leaderboard is to show how many points people have