As each user marks the whiteboard, it simultaneously appears on the other screens. Application sharing is a lot like remote control. In fact, it's really identical to it if one user can work in the other user's computer without restriction. In its simplest form, one user runs the application, say a charting program, and the other users simply watch the chart being built in their viewing windows. This is technically application viewing, not application sharing.
Application sharing allows different users to take control of the application.
Suppose user A launches an application and does a little work in it. User B then clicks the mouse or on-screen button, takes control and starts typing. Then user C, and so on, until user A gets ticked off and takes it back. If user A can gain complete control of user B's machine and can launch any and all applications, then application sharing is identical to remote control software. Both Netscape's upcoming Communicator, which includes Navigator 4.0, and Microsoft's upcoming Internet Explorer 4.0 with NetMeeting, include audio and videoconferencing.