The first time I met zero-width characters, (I suppose this was long before they became popular for "fingerprinting" text) it was in a weird bug where some java

The first time I met zero-width characters, (I suppose this was long before they became popular for "fingerprinting" text) it was in a weird bug where some javascript would fail due to a \u200b being present in a user-entered string (it was easily fixed by changing the method that we used to sanitise strings). I remember thinking "wow with these zero-width characters you could do steganography within text, even in a very short string". It looks like I wasn't the only one who had that idea.