I'm looking for a story where a girl can enter other people's personal "library", which allows her to borrow book, representing knowledge and personality traits. She uses this to transfer them to other people. When in a library, that person has their own librarian, which is represented as their stereotypical self-image. This librarian is quite stern about allowable actions, so she can't just grab everything: I remember there being a borrowing limit.
Later on, it is revealed that another girl can do basically the same with body traits, but that's represented as a museum. If I'm not mistaken, it turns into some kind of battle between them.
The basic premise is a bit similar to jsmt's "Katie's Library", but that's not the story I'm looking for.