Generally they all came in waves.
The first ones were all comic book and novel nerds and ex-trekkies autistically fixated in the sci-fi aspect of anthropomorphics, up to the 80s and 90's where they got washed away by the cartoon furfags who were coming of age to the tune of things like Tiny Toons and Bucky O Hare, all of them younger and orders of magnitude more deviant and immature. Then, those got old and jaded, and ragequit when the new generation of pseudo-weeaboo, videogame-playing, more social and roleplaying furfags came along, and things got too hectic for them.
Finally the web 2.0 came and the internet at large grew exponentially, and those precursor furries were themselves washed away by millions of people who had a mild interest in the content but none for the communities, learning art and producing it became much, much easier and cheaper and thus tight-knit communities mantained by artists dissolved. These are the furries of today, they are not removed from the rest of the internet, usually being furries as a side thing to a myriad of other interests since an active online presence is completely normalized, and thus they're not so socially inadequate as they're made very aware of the stigma and are more aprehensive towards sharing private hobbies.