Is it any worse than TV? That was creating 'stinking thinking' long before the internet.
I read a book called
Everything Bad is Good for You this year - it's about popular culture and its positive effects. I've always taken a dim view of computer games, but the section on them is pretty compelling about how complex they are now - in comparison with the likes of Frogger etc that I grew up with.
It's the same with some TV - yes, there's a hell of a lot of rubbish, but that's always been the case - but the author examines how much more complex plotlines have become, how much more interlinked characters are in changeable relationships, and how story arcs now run from series to series, rather than being resolved within each tidy, self-contained episode.
It's reckoned that this contributes to the Flynn effect, as does the fact that our education system deals much more with concept than it did in the distant past.
I think the issue with TV and the internet is that people are not necessarily very discerning. Not much you can do about that!