When I was in high school we used Win 95 and didn't even have the internet. the only use we had for them was typing up reports if we didn't have a computer at home.
today though, I manage the computers used by the same high school on a volunteer basis until my degree gets finalized. We use Macs for the high school kids, but the elementary lab is all Windows 7 and managed by someone else. We still block many things like Youtube and Facebook, but I would have to say at least 50+% is still widely accessible including many great resource sites for the kids to use for topics and other projects.