I have used a few Electronic Commerce systems since 1995 (First Virtual, MilliCent, ClickBank) for my on-line publishing service called "HyperInfo Knowledge Power Centre". Now, I am using PayPal as a pseudo-micropayment system by passing 2 search arguments (GET method) from PayPal's CGI "webscr" to my own "PayPal.acgi", and using the referer parameter. Although the per-transaction cost is still high, it is the closest one can get to universal micropayment as a customer enters only his/her PayPal password in order to purchase each on-line content once the PayPal account is set up.
A few years ago, I found the algorithm for the Gregorian Calendar in a HyperCard stack "Stack Ideas" to generate a calendar which is valid from A.D. 1582 to A.D. 4000. I then converted the script to an AppleScript CGI "Calendar.acgi", and created a webpage to dynamically generate a printable calendar on the fly. Although the CGI is somewhat slow because it is coded in AppleScript, the Calendar Generator has become quite popular, especially with visitors from ".gov" and ".mil" domains for some reason (accuracy?). The free service receives tens of visitors a day from all over the world, and I even received some donations, which helps keep the service up despite the dot-com meltdown.
