I’ve been shocked by the reception to Shuffle Buddy. Over 1 million people have seen my videos, and by my back-of-the-napkin math, I think a whopping 5% of all US teachers have watched one my Shuffle Buddy videos to the end (full retention).

I’m not an entertainer–and I’m not that pretty–but Shuffle Buddy went viral anyway. The two most successful videos were just product demos. When I tried to get fancy with it, the videos flopped. Based on the comments, it’s clear that people were excited because the product met clear need.

Product, meet market.

Business terms make me squirm, but I’ve just gotten a full-contact crash course in product-market fit. Everybody from kindergarden teachers to bus drivers have shared that Shuffle Buddy solves a big problem in their life.

This has been a massive validation of my life choice to pursue edtech development by becoming a classroom teacher, not a computer programmer.

As software products go, Shuffle Buddy is pretty simple. I rewrote the core shuffling algorithm in my hotel room at 1:30am. The computer science is not what makes it special.

Shuffle Buddy’s unique value is the ability to shuffle with rules, which is obvious to every teacher who has tried to randomize a seating chart.

Somehow, nobody had built it yet.