Where did "net send" go in Vista? It has morphed into msg.exe!

The general syntax of the MSG.EXE command is:
MSG {username | sessionname | sessionid | @filename | *} [/SERVER:servername] [/TIME:seconds] [/V] [/W] [message]

It also looks like it doesn't use a service for functionality either.

Read more about the syntax of msg.exe here.

I am sure "net send *" has resulted in some people losing their jobs over misdirected or inflammatory comments.

Nothing beats playing a 'dying hard drive' WAV file from a remote system though. IBM used to or still does have various "hard drive noises that are bad" WAV files available for download from their website. Mischief managed, indeed.