i mean in
can anybody tell what this rating system is about?

http://www.chess.com/article/view/chess-ratings---how-they-work
Its Glicko rating - Basically, each player starts at 1200. As you win and lose games your rating will go up and down. The degree of change is determined by the difference between your rating and your opponent's - as well as by each player's Rating Deviation (RD).
The Rating Deviation is an index of the accuracy of your rating given the amount of game data it's based on: It's a margin of error. (If your RD is high, it means a bigger margin of error.)
When you haven't played many games, your rating can move up and down quickly. Similarly, your rating moves less when playing an opponent with a high rating deviation because his or her true rating is less certain.
Of course, as you play more and more, your rating will become more accurate and less volatile.
i kind of understand your explanaion but my online chess rating is 980 is it good ? and will my rating improve if its under 980 or above?
Let´s say there´s plenty of room for improvement! I see that the average rating of your 3 online opponents till now was 1300+ ... that looks as though you´re playing players who are at the moment way too strong for you. Play a few games with opponents of similar strength to yours, and if you win then your rating will climb quite quickly again for the first few games.

your rating is relatively low ... but as you win more and more games it will improve... just keep playing. :)
http://www.chess.com/echess/myhome
In the bottom right hand corner you can enter the rating range of your opponents, try with maybe 800-1000 and see how you go on, if you still lose then adjust downwards accordingly (and go over your lost games and try to work out what you could have done better!)
I cant understand the rating system is this site so pls
help me! and explain