with some websites, they only offer you a certain number of minutes to watch a video. EX: Megaupload i think offers like 90 minutes. Which means if youre watching a movie there, it'll stop wherever you are and not let you watch anything else there for 24 hours. Illimitux nullifies that. (Or you could just let the movie buffer all the way through and then disconnect from the internet and watch it offline... or you could just torrent.)