I have it installed on 3 computers.  You can only use one at a time.  And there is a time limit as to when you can install it on another computer if for some reason you need to change where it is installed.  I don't know what that time limit is.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13