Illiteracy is hard to really pin down, as other commenters say. I'll provide another anecdata point too: Wife is a public HS teacher. Many of her native Englis

Illiteracy is hard to really pin down, as other commenters say. I'll provide another anecdata point too: Wife is a public HS teacher. Many of her native English speaking kids are illiterate yet use their phones like they were air to breathe. This may seem contradictory, but it hinges on the definition of illiteracy. They can read a word, yes, even type them out with a speed unmatched by anyone over 25, but they do not type more than 7 words at a time (again anecdata). That 7 word number is about the same as your working memory limit, and there seems to be a causation there, though it may be correlation. The kids just cannot read a sentence of any real length, like many of the ones posted on HN. Imagine trying to read Aztec Hieroglyphs. You have to decipher each word from the drawings on a stone fresco and it is not easy work to do this. By the time you reach the end of a line of these strange drawings, you have forgotten what the first word was. That is how the kids see reading, they try to decipher the word, and then about halfway through the sentence they have forgotten the first word. The meaning of the article is totally lost in the exertion of translating the symbols. That is how many of her kids are illiterate in the age of the Web.