That site generates a signature used for forums. It can show the following:
[*]MSN Screenames
[*]Current MSN Status
[*]Personal Status Messages including Current Music
[*]Current Display Picture
It won't allow you to open a conversation with them. MSN has to register that to be able to open convos. Like mIRC registers
irc://.
I suppose you could maybe grab the code from hotmail source code. I still don't know if it is possible. Never really looked.