I believe 'new' and 'rating' have no official use, but, I use 'new' to indicate that the player is new to the game.
Similarly there doesn't seem to be any official use for 'won' and 'don't record win stats'.
Perhaps the next version of the site, which is apparently under construction, will make use of these features.
Rating is probably for people who play tournament games, like Chess, where you get an official rating. It would be a way to signify if you are playing a very good player or a weaker one.
The site redesign was put on hold I believe... I don't think there are any plans to use these for anything anytime soon.