On both Microsoft and Lotus platforms, one person initiates an application share. The application you want to share must be active and in an open window on your system. When you click the Share Application button, the client lists all windows currently available on your desktop. When you pick one, that application appears on all meeting attendees' desktops. You can retain control of the application at all times. If someone else requests control, the application sharing feature asks whether you want to relinquish control or, if you've specified the appropriate setting, automatically relinquishes control.

Microsoft uses the T.120 protocol, an international standard for application sharing, to push the application data to other attendees. T.120 is built into all Windows machines; those on non-Windows platforms must find and download a T.120 client.

With Lotus Sametime 1.5, the first time a desktop enters a Sametime application share, Sametime pushes a pair of Java applets to the client. Any Java-capable browser can participate in the application share. To test this capability, we entered a Sametime application sharing meeting from a desktop that had no Sametime clients installed. The Java download took about a minute over a 55.6Kbps modem. After the download, we participated in the application share without a problem.

For both Microsoft and Lotus application sharing, we noticed a slight lag time while sharing an application over a 100MB Ethernet LAN and a more significant lag time over a dial-up connection. In both cases, however, the application share was quite usable.

Both platforms' ability to share applications with an unprepared desktop enables any number of useful functions. Only the application-share originator needs to have the application installed. Both Microsoft Exchange 2000 Server and Sametime push the application as an image to all participants. For example, we can be in an office in Massachusetts with a custom-developed database application, call a potential client in California, and have the client call in to our server. Within minutes, we can have the database application appear on the client's desktop and can guide the client through a demonstration.

Application sharing also gives you extensive remote control. Let's say Smith bought a computer from an OEM, and Smith's computer regularly locks up. Smith can call the OEM's Help desk, grab either the Sametime applets or the T.120 client, start an application share, and share his desktop. Smith can then let the Help desk person remotely "drive" Smith's computer, fire up and close applications, call up Control Panel, and do anything else Smith can do on his computer.