Reddit and hackernews too.

Frankly when I was a kid there were oldschool forums I'd frequent all the time.

I think this isn't a "kid" problem. I see just as many adults glued to their screens.

Wikipedia is informative, at the very least. It's the same reason why you don't see an outcry about people spending time at the library.

Youtube can be informative as well, although the majority of it is not. I consider YouTube to be as much of a problem as FB/Instagram, with the caveat that it can, by design, have useful content (which the other two cannot).