"To be most helpful a metaphor should be neither too far from nor too close to the thing being described. For example, if we say, "an organization is like a paper clip," this metaphor may be too abstract and distant to be helpful (although one could try!). However, if we pick something too close--"an organization is like an accounting department" or "an organization is like an assembly plant'-we are almost being tautological ("an organization is like an organization"). These metaphors are not "partial enough"; there are too many traits in common for them to spur creative thinking."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.