CGI (Common Gateway Interface): Is a way of interfacing web based applications with information servers and databases. CGI documents are server side programs that reside on a server and run when called through a browser. A CGI program can be written in any programming language that interfaces with a server and a browser (PERL, C#, C++, C, Java, etc...). Some examples of CGI programs are: A mailing list manager/distributor, a message board, auctioning system, visitor tracking, and ecommerce shopping carts. The list goes on.

CGI programs can provide varied and extensive functionality and a large or poorly written script will be slow to load. Many free CGI programs can be found on the web. There are sites dedicated to CGI programming and free scripts. The CGI programs on these sites vary in quality, functionality, detail, and efficiency, but the real advantage to free scripts is that they are free. A good CGI program can cost hundreds or thousands of dollars. Usually CGI programs are given away for a variety of reasons: The CGI programmer is developing a product and needs people to test the scripts for them, the programmer is trying to increase buyer awareness to establish clientelle, or the programmer is developing for the learning experience. A well-written free script can work well for most sites, small or large, but customizing a script for a specific purpose requires programming skills or a call to the programmer ; )