If Google chat can be integrated over http:80 seamlessly in the gmail interface in Chrome, why can’t Messenger? Is it a play on Microsoft’s part to prevent novice users from moving away from IE?
Web Service Meebo does exactly that. Microsoft simply doesn’t see it as something that’s worthwhile.
You can also try http://demo.java2script.org/gtalk/ (it has GTalk, MSN, Y!, AIM and ICQ).
It can be, see MSN Web Messenger.
Once you sign in, you see a list of contacts.
To actually use it as MSN Messenger, click on sign in on the drop down menu in the top right:
You can then use it to chat to people on a standard web page (Port 80 (or 443))