i'm learning about XSS! but i can't understand one part of XSS. It is like this:

hxxp://greetings.yahoo.com(1).message.1.2.1.12.text.decoration(2).12.3.12.3.yahoo.greetings.the.1<br>1.coulours.vn.view.ecard.12.212.12.3.412.14.124.414.414.trung.14.1@hotmail.com
what can't we do with that code?
if i want to steal cookies from the others(ex:hotmail cookie)! what can i do?
Plz explain me more about this part of XSS (@)!
thank u!