as UncleMilo said it's rather complexbut anime is like anything you can have knowledge about. When you first start off you know about only a few as you progress you collection of tapes and DVD's grows and your knowledge about different titles, the industry, and Japan itself grows along with it. I've actually given this a LOT of though over the last few years of being involved in anime. Right now I have over 80 tapes and DVD's in my collection and a bunch of anime related models, posters, scrolls, books, magazines (almost the full run of manga max, which was untill recently in my oopinion the best english language anime and manga mag) Levels in anime have a lot to do with how long you've been watching and what varitey of things you expose yourself to. For further info. Otaku no Video is a great look at the life we choose.
gee, sorry for so many words, maybe I have too much time to think about these things

