[abawany]

I never knew the idea was as recent as 2009 - I had naively assumed that they had been around since forever. RIP - he made the world a better place.

[newnewpdro]

The concept isn't that recent.

I've encountered them in various forms throughout the years, but the popularity has ramped up in the last decade as paper books became increasingly obsolete.

[mikeryan]

Myself as well. They’re all over Berkeley and I assumed they’d been here for some time when I moved here in 2010.