Was telling Iceman about my "new discovery" and he says it might be due to MessengerPlus!. Frankly, i don’t know. But i did find this setting… Plus – Preferences – Main – Conversations – Enable commands (special messages beginning with "/").
So maybe it’s not MSN after all. Hmm…
It seems to only work on Live Messenger Version 2008 (8.5) coupled with Messenger Plus. Tried on 8.1 with Messenger Plus but didn’t seem to work.