Go!Zilla is a proprietary download manager originally developed by Aaron Ostler in 1995, and later purchased by Radiate in 1999, for use on Windows. It is shareware and its previous ad supported version drew controversy among users and privacy advocates. Upon being acquired by Headlight Software in 2008, the ad-supported versions were discontinued and the software now offers a free limited trial.Go!Zilla was one of many download managers, also called download accelerators.