@androcat Edge-notched cards: https://en.wikipedia.org/wiki/Edge-notched_card

I think I first heard of them through the swtory of how the Whole Earth Catalogue used these to manage their subscriber database. Kevin Kelly's written on that here:

https://kk.org/thetechnium/one-dead-media/

@writingslowly

Edit: Hashtaggery.

#EdgeNotchedCards #WholeEarthCatalog #KevinKelly #KeysortCards #InDecks #InDecksCards #McBeeCards