My silly "secret chat" app got its first paying user. I emailed him. It turns out he's using it in a way I never, ever imagined.

Hey Reddit, So I have this little iOS app called MojiCode. It's a pretty simple side project of mine: you type in text, and it spits out a string of emojis. The idea was for friends to send goofy, coded messages to each other. I built it to be a fun toy, basically. A few days ago, one of my first paying users emailed me about a minor bug. We sorted it out, and just out of curiosity, I asked him: "By the way, what are you and your friends mostly using the app for?" I was expecting to hear something about secret crush confessions or gossiping in class. His reply blew my mind. He said: "Oh, I don't use it for chats at all. I use it as a password manager." I was so confused, so I asked him to explain. His system is brilliant: He set one single, memorable Super Key for the app. Now, whenever he needs to save a password, he encrypts it with MojiCode. He then saves that harmless-looking emoji string in his unsecured notes app. To anyone who snoops on his phone, it just looks like he's saving weird emoji combos. But for him, he only needs to remember his one single Super Key to decrypt any password he needs. I, the creator of the app, had never even considered this. I made a toy for passing secret notes, and this guy turned it into a personal, low-tech password vault. It's such a wild and humbling feeling... Has anyone else had their project's users completely surprise them with an unexpected use case?