The rating system has now been installed in the following games: 

Adders
Diamond Slide
Entrapment (available only if you play "Hardest" difficulty level)
One to Ten
Quadratic Rush
Trio Match
Word Funnel (available only if you play multi-level games)
Word Spin
Zap!

When you look at the game options for each of these games, you will notice that there is an option labeled "Use the rating system." This option is currently checked, and can't be unchecked. Soon you will have the option to turn ratings on and off, depending on whether you want to play "just for fun" or want your games to count toward your rating.

One player asked: "Will you be able to change that option AFTER you start a game?" And the answer to that question is: "No! Because if you could do that, you could unfairly boost your rating by shutting off the rating system any time you were having a bad game!"