Time Restricting a game on the Mac

I'm looking to release a demo or time restricted version of my game on Apple.com and wanted to know what would be the best approach.

Should a file be created in a secret place and checked to see if the game has expired? I'm not familiar with the registry equivalent on a Mac and would appreciate any advice.

Some people have suggested to me that I should have two versions and just have them download the full version. But I wanted to know all my options first.

I'm not trying for anything that will stop a determined hacker, just a basic preventative measure.

Thanks in advance.

The Mac does not have a registry, which is a good thing. However, there are the folder structures /Library/Application Support and /Users/<Username>/Library/Application Support that could be used for storing that kind of information, preferably as hidden files (files with a leading "."). You'd need superuser rights to access /Library/Application Support, though, which adds complexity to your installer, but you'd be writing a system-wide setting in exchange for the trouble.

Shareware is a commonly accepted way of software distribution in the Mac world, which basically translates to that nobody wants to download a second version of the same software when you can just enter an activation code in the version that you already have. (I pretty much prefer that myself.)

Thanks for the information. This is very helpful.

For future reference, some people on the Indie Gamer forums had some suggestions as well:
http://forums.indiegamer.com/showthread.php?t=12178