[nervuri]

Zero-width characters can be used to covertly watermark text and to figure out who copied text from a page and pasted it somewhere else. Server software can encode a hidden number between every few words, which corresponds to a server log entry with your username (if logged in), IP address, browser fingerprint, etc. I wrote more about this here:

https://nervuri.net/stega

I think the best solution to this type of problem would be a clipboard utility that warns you when you copy text which contains hidden characters, homoglyps, rarely used whitespace characters, etc.