The people who are into this were always there amongst the nerds. They just never spoke up out of fear and social ostracism.
Furrys are not a new "Internet" thing, the fandom has been active since like, the 70s when it branched off other fantasy fandoms. It was all started by a small group of people going to scifi cons.
The greybeards are the Linux-Boomers now, the nerds with glasses became the new greybeards and trans people, gays, furrys and femboys are the new nerds with glasses. The circle seems to close.