People spend more time in front of computer now than before, and this means less time actually interacting in three dimensions. This is obviously not helpful and needs no detailed explanation.
“But wait,” you say. “The internet allows like-minded people to find each other, to get together, form groups, societies, go camping, hunt for children online, say hateful things under the influence of anonymity, and other great stuff.”
If one associates exclusively with others of like mind, divergent ideas are less likely to meet each other and be reconciled, over beer. Instead, a kind of intellectual or ideological incest takes place in which highly specialized (e.g. perverted) views are cultivated at the expense of diversity or “genetic drift.” People become more radicalized rather than being forced to confront and deal with different points of view. Conflict resolution skills are taught by first-person shooter video games rather than the collective wisdom of real adults, or a rock falling on your head, for example, which can teach you a lot.
This is similar to the ill-fated notion of being able to choose your own musical tracks rather than an entire album. Almost invariably, the songs you choose will not be the ones you most need to hear. And again, an opportunity for growth is missed.