Same goes for Audiogalaxy. (Doesn't AudioGalaxy's founder occasionally show up on this board?) It was a web page where you could see what music people were sharing, search for it, and then download it. When you downloaded a file, it would download a small stub (via the browser's mechanism), which would then be opened by the AudioGalaxy service on the client, which would queue up the file for later downloading.

I remember arriving at college, where each person had their own pet ways of downloading MP3s. Within a week, my whole dorm had basically standardized on AudioGalaxy.