how URLs with Guid Work ????

Hi,

     in some sites i have seen that they provide URL as below

             http://mysite/882e63c8-d76a-102b-a434-00055d4a971b   so that it can be mailed to someone and pasting the URL
    directly on Browser Address Bar
automatically takes to the desired page.
    Also similar behaviour can be seen when we register at at particular site and it sends the
Verification URL to mail, by clicking of which we
     get to the site for confirmation.


      How is that possible ???

      How such URLs work ??
     Any article or site where this kind of implementation can be found ?

 
    Thanx in advance
...