Welcome to the new age of computer-powered math where anonymity is not a guarantee.

Plenty of discussions in this thread show why. Anonymous screenshot or picture? Image watermarks -> anything from subtle color changes, to sans/serif font changes, to word replacement. Anonymous text or summary? Word replacement, letter biasing encoding, etc. Anonymous audio? Inaudible frequencies, audible waveform deformation encoding, etc.

Nothing's out of the realm of possibility for the paranoid.