By what, do you define someone as a furry?
You jerk it to ungodly amounts of Anthro porn. You like anthro art, draw it, and/or dress up as an anthropomorphic animal.
I really don't do any of these three any more
except have a tiger woman fetish lelelel, so I have no real say about furryism. Other then: "Most of them are real fucking weird." "They make really stupid comments that make you think that they have mental issues (as if they're talking to the character itself, and no they're not doing it for shits and giggles... they're being serious and it makes me cringe the fuck out)." "They're all really nice with the weirder ones being the more insecure and "extremist" of the community. The lot of them are regular people with an odd hobby. The rest are mentally unstable douchenozzles that need to burn."