If ideas A and B have one or more ideas in common (say C, D, and E), then chances are, ideas A and B are also related. The power of simple matching by transitivity should not be overlooked. Making just a few connections allows a connected graph of ideas to “bootstrap” further connections in a positive feedback loop: one linkage between ideas begets more linkages between ideas. Indeed it is by a similar positive feedback loop that humans acquire an understanding of abstract concepts (as an example of this, dictionaries are built of relations between concepts).