did it? i think i've heard of messenger plus! but admittedly i haven't used it, i've mostly been using MSN 6.2 (was using 5.0 for a bit but that started freezing up on me a little while ago ago so i had to 'update' to 6.2)
If i recall correctly, Messenger Plus lets you set a custom message under your name for other Plus users to see, you can color your text, there's additional emotes, even animated ones, you can make custom emotes, change the messenger's theme and color, i think you can even send sounds through the messenger