Jamie Zawinski outlines a hypothetical program - vast volumes of email:

"There are other interesting data-visualization possibilities here as well; since really what we have is nodes and connections between them, tools like graphers and histogram charts might be applicable as well, to answer questions like

* show me a graph of the age-distribution of my unanswered mail, or,

* show me a graph of people who are known to have directly exchanged mail with each other so that I can see the "clumping'' of my correspondents."