From GSA:

The GSA Auto SoftSubmit is a program designed to submit your software to hundreds of web sites. It will save you a lot of time and money since its fully automated. Promoting your software has never been easier. Load a PAD file and let the program do the rest. The program gets updated several times a month to make sure all included providers (over 5900 and growing) still work. There are a lot of web sites with shareware and freeware. Is your application listed on those? This program will take care of it and submits your software to all of them. But why is it so important to have your software listed there? Not only that more customers will find and buy your software, but also your ranking in the search engines will dramatically rise since many of the shareware sites have a back link to your web site.