Google Analytics can track pages and average time spent on page. It can even track visitors flow.
Everyone should get an analytics account and see the insane amount of things that Google can track for YOU, for FREE with just three lines of extra code on your page.
Nobody knows if you're actually reading the words, but based upon whether you scroll through the entire content, and possibly factoring in how quickly you scrolled, they could have an educated guess. If you didn't scroll at all, you probably read the first paragraph, if that. If you scrolled quickly to the bottom, you probably skim-read. If you scrolled to the bottom with a lot of pauses and it took minutes, you probably read the whole thing.