Original: Artwork featuring original characters of my own creation. Most of my stuff is here.
Fanart: Artwork featuring characters created by others -- from anime or games, and characters belonging to friends.
Scraps: Unfinished, old, or just-not-that-good work. Lots of sketches and paintchat stuff. These aren't organized; they're just in a directory.
Collab: Collaborations with other artists.
Gifts: Artwork other people did for me. Love them. I do.