Comment Zip disks filled a gap reasonably well... (Score 3, Interesting) 247
Back before USB flash drives were widely and cheaply available, the only way to easily move around more than a few floppy's worth of data was the Zip drive.
100 MB was a lot back then. Even though the drive itself was not ubiquitous, the parallel port model could be easily transported, and it was supported on multiple operating systems. Macs were supported with SCSI. In some institutional environments, you'd find internal IDE zip drives. My local library branch had computers with internal drives, and for a few years it was the primary way I was able to download anything more than about 20 MB off the internet (hi-speed internet unavailable at home).
CD writers were expensive (my original 2X writer was $300), and came with all the problems of read-only media. Of course Zip had its problems - the drive itself wasn't very cheap, nor the disks, and of course there was the click of death... but all in all, it was IMO the most versatile portable storage medium we had between floppy disks and USB flash drives. Lugging around an IDE drive and opening up whatever you wanted to attach it to wasn't always an option