The idea behind the doorbell page is to allow people to get my attention when I'm at home so they can talk to me on MSN Messenger. This saves people having to phone my house. This is used a lot by members of my family who are over seas. For example my brother who is currently living in Germany can contact me by going to my website clicking on the door. This is only really any use for people who have my hotmail address in their MSN contacts.
When the visitor clicks on either the door or the bell they here a sound played by the browse. A CGI script is called on my web server at home which is always switched on. The script creates a temporary file and logs the date, time and IP etc. A programming running on my web server sees the temporary file and plays the same sound the visitor heard. The temp file is then deleted.
If I am in your MSN contacts and you do knock on my door to contact me, make sure you send me a message from MSN so I know who it is. This saves me having to ask all of my many contacts who are online if it was them. If however you are a visitor to my site who is not known to me then feel free to leave a message on my message board.