"SourceGuardian has been a tremendous success for me. I have been putting an encrypted tag along with code the scripts cannot run without in an include file, so I know where my scripts go. On 12/26/02 I noticed one guy had a script on six different sites. It turned out he was selling the sites as turnkey solutions on eBay for $299.00 each or highest bid. Anyway, eBay took all the sites down in less than 3 hours. I wouldn't have caught him if I had not known where the scripts were and seen the for sale signs.
The encryption hasn't hurt sales at all. In fact only one person has even questioned my use of the encryption. Bogus transactions appear to have been cut down to 0. I no longer get those "how much for all of your scripts?" emails.
I may even start offering some of the scripts on a "try before you buy" basis. Overall, I would say that SourceGuardian ranks up there with phpMyAdmin as the most important development tools I have ever used.
Take care and thank you very much,