Floppies
It just hit me. I learned how to code via an article in a Dutch school magazine (Taptoe), which explained how to create a website on a floppy disk. They were already old, but at least our computers had the drives still. The article just explained how to write flat HTML, but it was enough to spark this fascination that ended up being my job.
What hit me is that actually most websites these days won't actually fit on a 1,44 MB floppy anymore. (The content on this site already is more than 1 GB.) It would be a nice challenge again, to make a website fit 1,44 MB.
Related to this is the 10 KB Club, who try to keep their homepage under 10 KB. My site fails that test too, but at least the homepage fits a floppy.