Most content creation is pretty obvious: Art, costumes, writings, photography, and so forth. The big question: Would you consider costumed performance to be a form of content creation?
I would, for many (but not necessarily all) performers. Like a dancer, the creator of a distinct character through performance has the capability to entertain, and to provide a point of inspiration for derivative works (art, fursuit performance, photography, etc). Like dance, the nature of the performance is temporary, but can be recorded and admired after the fact. I can think of more than a few people who are fans of the way that other certain people perform in their costumes, regardless of the way the character (or costume) looks in a static sense. Similarly, I do know people who just meander about in their piece of wearable art, showcasing the costume without layering a created personality on top of it. Subtle follow-up question: Is it possible to recognize the quality of performance in any way other than popularity, and is it possible to evaluate performance any more or less quantitatively than evaluating art?
P.S. For the sake of the conversation, I'm setting "content creators" aside from other important fandom contributors, including convention staff, community website coders and sysadmins, and other people who add to the fandom's ability to come together.