Perl is a very popular scripting language that's used to make various web-oriented applications, including CGI scripts. One of the characteristics which distinguish it from alternative programming languages is the employment of modules - parts of Perl program code which perform predefined tasks and they're widely accepted. Basically, rather than creating custom-made program code to do something or pasting tens and hundreds of lines of program code inside your script, you can "call" some module which is already available for this particular task and use just several lines of code. Consequently, your script shall be executed faster because it will be smaller. Using modules will additionally make the script simpler to change due to the fact that you will have to search through a smaller amount of program code. If you intend to use Perl on your site, you have to make sure that the required modules are present on your server.