How much time do girls really spend on their appearance? I've only really discovered that there were any girls playing video games, or lurking around forums/the chans very recently, within the past couple of years.

In malls, the female shopping space, there's only clothes shops as far as the eye can see.
Makeup is pretty much universally worn among girls.
Pretty much any girl I've met, they consider working/experimenting with some aspect of their appearance to be some kind of hobby (nails, etc.)
As for Internet sites, I had this impression that the only places you would find girls on were Facebook and Instagram, two sites also very oriented around on sharing photos.
But you couldn't be so focused on their appearance that you don't have time for anything else could you?

In that case, why does it still seem like girls who own/use a computer and meaningfully engage with the Internet seem to be so vanishingly rare? To me, and at least most men I've ever mixed with (I guess there are the sorts who find clubbing or watching sport and stuff fun instead), doing things on the computer seem to be pretty much the only fulfilling use of free time.