Similarly, I've been writing respectable, sophisticated software for decades but I'm fairly certain that my most widely used piece of software, by a wide margin, is a mildly pornographic app ( http://driftwheeler.com ) Other projects I've published have a trickle of users. But this app, published in 2017, has a continuously growing population of users from all over the world. I get email every day asking whether soft…
Probably the lesson is most stuff boils down to product market fit. Speaking of product: the app is not available through play store, isn't it?
But if you Google "porn app", the 4th or 5th search result (SexTechGuide) is a page that features the app, with a review, pros/cons, and the funny icon.