Everyone is right to dunk on Yahoo and "tumblr is the new PDF" because yeah, everything about that era was stupid.
But the PDF thing kinda makes sense. Bear with me.
See, in the 1990s before PDF files there was almost no way to generate a document on a Mac and read it on a PC. Or vice versa. Businesses struggled with how to email important documents around and guarantee they looked the same on the other end, regardless of what computer & software the recipient had.
Adobe changed all that with PDF.
Since Acrobat Reader was available (and free!) for Windows & Mac, suddenly the problem went away. Everyone knew how to read a PDF. Adobe became a universally recognized brand overnight even if you'd never heard of Photoshop, because everyone had goddamn Adobe Reader installed.
Because of that, every tech company yearned to be just like Adobe: invent something universally desired, used by billions of people.
Fast forward to a Yahoo/tumblr meeting sometime in 2013/2014.
Tumblr development staff demonstrates how the back end of tumblr works, which (honestly) is revolutionary as compared with how any other social media site worked at the time. Each tumblr post is composed of blocks of data, any one of which can be text, sound, an image, a movie... anything. These blocks of data are threaded together into what looks to the user like one cohesive message (a single tumblr post) but under the hood it's magic.
Further, the mechanism for doing this can be standardized. In other words: tumblr could, if they wanted, publish the standard as a way for ANY social media site to manage its data.
If other sites did that, then they could trade messages with tumblr! Imagine posting a message on tumblr and reading it on Instagram. Or see twitter messages natively on your tumblr feed. I mean personally, that's a horror show. But the concept is interesting.
(In fact, that's how Mastodon and the Fediverse work in 2025. Each Mastodon post is a standard chunk of data that any website can read & display, assuming it understands the underlying ActivityPub protocol and plays by its rules.)
So the Yahoo executives attend this technology demonstration and one of them quite visibly has a light bulb wink into existence over their head. The light bulb is an old school incandescent, 300 watts at least, and glows furiously bright.
The Yahoo exec stands up. His chair knocks backwards.
"OH MY GOD," he stammers. "This tumblr thing could revolutionize social media. It'd be like the new PDF!"
Then blood shoots out of his nostrils and his head explodes, but all anyone ever remembers from that meeting is "PDF".
@sreegs or @cyle or @jv can probably explain it better, but that's what I remember hearing at the time. Please feel free to correct me.
