WireframeSketcher licenses are based on named users. A named user is any individual with the permission to use WireframeSketcher software.
A named user is counted towards the user limit at any time, regardless whether they are currently using the software or not.
Licenses are assigned to people and not to machines. Each named user can use WireframeSketcher on any machine they own and use.
Note that WireframeSketcher licensing is not based on concurrent users.
However WireframeSketcher licenses can be transferred at any time.