And while iPod could be connected as a drive via firewire, that was never the way to add/remove music there, since (for better or worse) it was never a dumb "play this folder" type player, but maintained a associated library format with metadata etc.
That latter choice also put a human in the loop, since you were probably interactively importing media (whereas media-indexing usually happens in the background.) This meant the human could be relied upon to notice and fix bad ID3 tags, which was a big problem for most audio files of the era and made many MP3 players a useless "unlabelled warehouse" when you had a lot of files on them.
Great memories
You could never drag music to the iPod and have it recognized by the music player.
You could always drag random files to it and have it work as a hard drive. On Windows it was NTFS (Fat32?) on Macs it was HFS+
And even with music it was easy to drag music files from an iPod; they were merely in a hidden folder. I don't remember trying to drag music to an iPod with the Finder because it used to be so easy to do that with iTunes.