BARCODES! No one cares about 'em. Yet they were once exciting, cutting edge tech. Heck, old computer magazines often had entire sections dedicated to UPC scanning and software. So I finally got a PC barcode reader kit from 1994 and used it with some POS applications! And Duke 3D.
Yes, all the computer-paper interfaces are cool IMHO. That DataMatrix and QR are mainstream now I mostly like too.
What I don’t like is the wide reliance upon open Internet connectivity, and even worse, upon services in it.