dhtmlchess.com

Hello Alf,

It would be a good idea to improve the user's rating system.

First, it would be great if the user could have different ratings to different chessbases.

There is also a better system to calculate the rating: Giving rating to the users and also to the problems.

Here there is a free code:
http://www.glicko.net/glicko.html

There is also a tactics app than you can try to have new ideas:
http://innokuo.altervista.org/chesshero.html