I myself used to think ´rs´ might be an abbreviation of ´revolution system´, but then I found this page on the Wayback Machine (a long-term version of the Google cache, if you will). The page reads:
Q: What IS the IGN Downloader?
A: The IGN Downloader is software which greatly enhances the efficiency and speed of downloading IGN content for our users. It greatly improves the speed and quality of service we are able to give you. IGN Downloader can increase your download speeds dramatically, sometimes by as much as 200%
Red Swoosh, under testimonials, quotes IGN as saying:
Red Swoosh provided us with a robust Content Grid product that scales to handle our 10 million users, and our ambitious delivery goals.
So, the IGN downloader used to be an IGN service in collaboration with Red Swoosh. There you go. Proof.