The Send Message view is based on Microsoft's NetSend command and is limited to its restrictions. Microsoft removed the Messenger Service and the NetSend command in Windows Vista, Windows 2008, and Windows 7.
The DameWare Remote Support Send Message view provides an easy way to send messages to other users, computers, or messaging names on the network. Use Batch Processing to send messages to multiple individual systems, or broadcast messages across workgroups and domains. For additional information about Batch Processing, see Batch Processing.
The Messenger service must be running to send or receive messages. You can send a message only to a name that is active on the network. If the message is sent to a username, that user must be logged on and running the Messenger service to receive the message.
Some operating systems and service pack levels limit the number of characters that a broadcast message can contain. The lowest cap is 117 characters, but caps vary depending on OS and service pack.