Way broader than Nick's
I think anyone who's a fan of content starring anthropomorphic animals is at least displaying furry tendencies. I know most people draw the line more specifically to like "People who have fursonas" or "people who consume niche internet content" but I know furries who do neither of those things, and if I were to have to encompass the entire gamut of people I know who are all definitely furries, the only line in the sand that encompasses all of them is the former.
Do note that "is a fan" goes a bit further than "has seen it and/or likes it." Someone who saw and thought
Zootopia was a good film isn't necessarily a furry, especially if they forget about the film and quickly move on with their lives, but if they get immersed enough in
Zootopia culture and community that they consider themselves a "fan", I think they've crossed the line. I suppose it's possible that someone can be a fan of something furry while not taking any interest in the anthro aspects, but said aspects are so intrinsically integrated into the whole of the product I would still nonetheless categorize them as a furry whether they like it or not.
