I don't have fixed IP addresses (on DSL or cable) so this is a life saver for the remote operation of my machines. Whenever the IP changes (or the service goes down) it notifies me of the change by e-mail. So far it has never crashed or failed. As for CPU cycles used on a G4 or G5 with OS X 10.3.8, it sits at 0% except when it's actually checking the IP address or e-mailing the report. And you can set how often it performs a check in prefs. Ipanema is a utility with a very limited purpose and it performs that function flawlessly for free (although a donation is the only way to turn off a nag screen at start-up). I hope it will still work with Tiger.