This is what happens when you don't read release notes.
Sign-in and messaging in multiple locations - You asked for it,
now you have it! You can now sign into Messenger from more than one
computer at a time, up to four at once. Simply sign into Messenger
from one computer, install Messenger on another computer and sign
in using the same account. (Only works if all computers are running
Messenger 9.0 Beta. Currently enabled only for users whose Windows
Live ID country is US or Canada.)
Bah!!!
