What is anime? All animation from Japan? All animation of a certain style? Then what about Japanese animation outside of that style? What about the international productions? An old debate, that is surprisingly common in more ad-hoc anime viewer groups; youtube comments, gamer forum threads, and personal discussions, and rarer in the blogosphare, on anime-themed sites, and in other groups self-identifying as the “academic” opinion leaders of otaku culture.
Maybe it’s because the latter doesn’t want to deal with something that is seen as the petty whining of obsessive-compulsive categorizers. Or maybe because after a certain amount of anime watched, the borderline cases will start to appear more and more clearly fitting into one group anyways.
It’s easy to believe that Avatar or Teen Titans are exactly like anime, when all the “other anime” that you have watched, is limited to Death Note, Naruto, and Elfen Lied. Then as your MAL is growing several hundred titles long, you will start to detect hundreds of little differences between them that you might not even consciously notice or at least you couldn’t describe, like the different emphasis on lip-synching, the details of background scenery or in shadow effects, and the exact way faces are drawn. (beyond just “small noses and big eyes” (Because seriously,that’s about the most generic description you could give for pretty much every cartoon ever)).
And then the plot starts, and it’s even more obvious that there are plenty of fundamental differences between how a western and a Japanese writer would think about storytelling. Even when they are actively trying to imitate each other.