Looks like some people are reporting that MSN Messenger is blocking users from sending messages with www.youtube.com in the text. No one knows if this is intentional or not as there are no official notes or releases from MS yet. I just tried it and I can confirm that it’s still blocking.

…I loaded up a network packet sniffer to find out exactly what’s going on behind the scenes. Technically, the message packets are in fact sent to the Messenger servers (so it’s not being blocked at your client), but the server sends back a negative acknowledgment (NAK) packet instead of an acknowledgment (ACK) packet. Simply speaking, the server is refusing the message.

See here.

ummm i dont think i had a problem with that yet odd

Thats odd, i don't use my MSN much anymore, but i had a buddy send me a Youtube like a week ago and it didnt have a problem.

Hey, I'm just reporting what the "big guys" say. Don't kill the messenger. Bwhahahahaha.