Most of that information is probably only one the internet because it's from the Harry Potter series. In the Harry Potter universe, that information might not be on the internet, especially if it's supposed to be secretive like the Horcruxes. They do spend a lot of time researching though so the internet might be useful. The only problem is that the great reveal of some of the information is an important part of the plot line (like a mystery) so it would probably have to be written differently. I also think it would've been a good way to learn about depression and PTSD (there's even information written specifically towards teenagers/about how it affects teenagers) that would help Ron and Hermione understand Harry better and finally get him some help (as soon as they can find a psychiatrist in the wizarding world, yeah good luck with that guys.) I'm little worried about Harry though because a depressed, traumatized, possibly suicidal teenager having access to internet could end badly because it might encourage self-harm and suicidal behavior. There would probably also be a lot of porn researched (Ron's would probably largely include women that resemble Hermione.) I'm not sure how complex the internet was in the 90s though.