Other web applications are offered free of charge, often generating income from advertisements shown in web application interface.

The movements and arrangements of these fiducials are interpreted into gestures that act as interaction instructions for the projected application interfaces.

There are tools designed to provide key-agent functionality for both symmetric and asymmetric keys; these usually provide ssh-agent functionality as one of their application interfaces.

However, systems are underused because the choices of control mechanisms and application interfaces are too diverse.