You'll have come across it before: the internet threatens old-style reading - that is, the reading of books. Here the theme gets an outing from Mark Morford in the LA Times. And he's someone who loves, who adores books; though he hardly reads them any more. He knows what the solution is, but still, he wants to run with the idea that spending time on the internet messes up your brain for 'proper' reading.
Me, I don't get it. It's true that sometimes, if you have to switch rapidly from one type of activity to another, there can be a problem. For example, if you've been in charge of boisterous young children for some hours, and have to sit down immediately to something requiring intense mental concentration, you may find that you'd be better placed coming to it after a break. Switching from much online hopping and skipping about to serious reading is no different. The problem isn't with the internet. And the solution is straightforward. Here's one version of it: however much of your spare time you spend online, spend at least 50 percent of that reading (books and such). You'll find you can do it just as well as ever. This is if you want to. And if you don't, then you don't. But that's you, in that case, and not the internet.