Can anybody explain me how exactly the rating of any user is calculated ?

I did’t get it from this link also

http://blog.codechef.com/2010/12/27/a-surprise-in-store-this-new-year/

Please Explain us with some example.

I will really appreciate your effort.

and Please explain me some think about **ELO seed based rating system**.

I really want to know about it.

thanks

**Admin EDIT**: We have introduced a new rating system. Please have a look at this.