It's a wonderful and harmless diversion from the grind that reality sometime brings. There's ample opportunity to create, share, interact, and socialize with like-minded people. The level of involvement is limited only by one's imagination and budget, but there are even ways around those constraints--thanks to the internet.
One may even combine furry with other hobbies, sports, and everyday tasks for fun. A YouTube video of someone cleaning the snow from his car may be of little interest, but if that person was in a fursuit--it becomes comedy.