Some of WinMessengers features:
True SMB (WinPopup, net send) compatibility WinMessenger is ceritified Designed for Microsoft Windows XP, 2000, Me, 98, Windows NT application

Some software makers claim that their messaging programs provide standard WinPopup compatibility, but they implement only the most basic type of SMB protocol (for example, in such software you can't send a message to a username or to a non-Windows operating system).

WinMessenger offers complete implementation of the SMB protocol, so with it you can do everything you can with WinPopup. For example, you can send a message to a Novell user, receive messages from Linux systems, send and receive messages to/from Windows NT servers and so on. Available for all Windows platforms