That is the new book by Gretchen McCulloch, here is one excerpt:
The passive-aggressive potential of the single period started being reported in thinkpieces in 2013…The string of dots got a thinkpiece in 2018, though it has been popping up in comment threads since at least 2006, while it cousins, the hyphen and string of commas, have been less extensively reported but have occasioned long comment threads on blogs and internet forums. Despite the fears mongered by headlines, it’s not the case that the passive-aggressive meaning has killed all other uses of the period. The linguist Tyler Schnoebelen, who’s definitely younger than the peak dot-dot-dot generation, did a study of periods in his own 157,305 text messages. He found that, true, periods were rare in short, informal messages — ones less than seventeen characters or containing lol, u, haha, yup, ok, or gonna. But they were still often found in messages longer than seventy-two characters or containing words like told, feels, feel, felt, feelings, date, sad, seems, and talk. The added weight of the period is a natural way to talk about weight matters.
Most books on the internet I find vacuous, this one had some material of interest, though perhaps for some people it is too navel-gazing. But if you are going to spent that much time staring at a screen, and typing text into little boxes, surely you might wish to understand it better. Most of all, I enjoyed the discussion of how different generations have learned to use the internet somewhat differently, depending on when they started.