RealPlayer is very intrusive. It popped up on its own, while I was browsing. It immediately began downloading an update, and then it threatened to restart my computer. Luckily, I was able to opt-out of that. Unfortunately, it still forced my web browser (Firefox 2.0) to shut down. Luckily, Firefox’s built-in session management restored all my windows and tabs. I did not accept RealPlayer’s license agreement, so the player was not installed. Fight back!