In 2003, there were very few websites where what you saw depended on your login information. For the most part, the entire web was a bunch of stateless pages where what you saw at a URL was what I saw at the same URL. There was no real opportunity for interaction with sites in the browser (anything like that required a browser plugin to run java applets or flash/shockwave content).

RSS was such a game changer in that it really did change the way people consumed content. I could load a blog and it would only show me the posts I hadn't already read, instead of naively showing me the whole thing. Suddenly there were states, and things could be marked as read or unread.

And when someone realized how to combine RSS with actual audio or video media, that was the first real semblance of "on demand" content where anyone could press play on current, timely content at their own schedule. DVRs had basically just been invented, and cable on demand content wasn't widespread yet. YouTube didn't exist, and the best place on the internet to watch a trailer for an upcoming movie was apple.com, where they used movie trailers to try to persuade people to download QuickTime to play those videos.

So yeah, automating a download to your computer to automate pushing content to your iPod was a huge step forward, and basically sold itself.