We all know about those annoying nag screens that shareware/trialware programs pop up on program startup. I was wondering how these programs register their existence in my OS X system. When I delete trialware from my system and install again, the software intrinsically knows that I have installed the software already in the past and that I have X number of days left in the trial. How does it know this? I've tried searching for relevant application preferences and settings in /Library and ~/Library before with no success.
I ask in an attempt to understand the technology behind these piracy protection systems, and not in an attempt to dodge the protection schemes.
Actually perhaps this discussion should be about all OS X applications that write to Library/settings. If I install programs X, Y, and Z, I could potentially have files for X, Y, Z in my Library/settings. These files remain even after I delete a program. How does the average user deal with the extra baggage left by unwanted programs?