I think the main problem is that communication technology makes it easier for people to fall into sins, and harder to stay away from sins. If you internalize the idea that envy, rage and sloth are bad for you and should be kept out of your head, then Facebook and Twitter shouldn't pose much trouble.
Good point, but beyond internalizing those ideas, you also really have to be on guard these - the technologies in question are ubiquitous. They are almost inescapable and are designed to get you hooked. It's easy to say look something up on reddit and then dive into tangentially related material which ends up turning into procrastination.
