About Extension Scripts
Extension Scripts are scripts created to extend the capabilities of Mojo Mail. Each extension script has to be installed and each script may need installed differently, but usually you need to upload the script to your hosting account (and usually in a directory in your cgi-bin, like /home/account/cgi-bin/mojo/extensions) and change the permissions of the script to 755. Any other variables that need to be set will most likely be at the top of the script itself, coupled with directions.
Scripts that end in '.cgi' have been written to be accessed from your web browser, just like a normal cgi script.
Scripts that end in '.pl' have been written to be accessed from the command line or by a cron job or having a message piped to it. Many of the scripts that end in '.pl' may not work correctly on non-UNIXy servers, like Microsoft IIS.