Welcome to chess.com! Hope you continue to enjoy it!
Chess.com uses an elo rating system (http://en.wikipedia.org/wiki/Elo_rating_system). Basically you start at 1200 rating, then gain points when you win and lose points if you lose. The amount of points gained/lost depends on your current rating relative to your opponent's.
As for chess books, I haven't read any, so sry :( I only started playing chess about a year ago, and even though i enjoy it, I'm not committed enough to invest time in reading chess books.
I have only just found this site today after years away from playing chess due to my friends lack of interest. Thankyou all! As I'm a bit rusty now, can anyone recommend any good books to help me pick up my game? Also how does tis rating system work?
Sorry if this is a repeated post, I just couldn't work out how to backtrack through all the topics!
Thankyou guys :)