How does shareware store its usage?
OSX Applications come in a .bundle file which is basically like a ZIP or other archive file in that it's actually a sort of folder. In that way all of your program files and dependencies are in one, neat package. Sometimes, though, other information like preferences will be stored throughout the system. Typical places to look are /Library and /Users/(user)/Library. Warning - do NOT delete anything unless you really, really want to mess something important up. If you have a legitimate concern I would suggest contacting the developer and asking for assistance.