title: Implementing a 30 day time trial
body: <p>Question for indie Mac developers out there: </p>
  
  <p>How do I implement a 30-day time trial in a non-evil fashion? Putting a counter in the prefs is not an option, since wiping prefs once a month is not a problem for an average user. Putting the counter in a hidden file somewhere sounds a bit dodgy - as a user I hate when apps sprinkle my hard drive with random files. Any ideas?</p>