We already know that places like Facebook monitor our every keystroke and store them for posterity. Yes, they hang on, also to the text you regretted, backspaced, and never published. It would seem utterly unprofessional, and potentially detrimental to shareholder interest, for them to not also keep track of timings and typing rhythms. Which makes me wonder how much mood analysis, lie detection, and other psychometrics they really have collected on us all over the years, given the right kinds of algorithms to run the lot through.