Rates differ according to definition. It's clear that YouTube commenters aren't illiterate in the sense of total inability to read; they're typing, after all.

Rates differ according to definition. It's clear that YouTube commenters aren't illiterate in the sense of total inability to read; they're typing, after all. 'Functional illiteracy' encompasses people who can read and write, but not with the fluency required to function in society, for instance, when understanding and completing a job application. Let's face it though; do you really think you live in a society where >95% of the population can read and write fluently? Educated people tend to live in a bit of a bubble, surrounded by others like them, but YouTube tells a different story.