In the above diagram (created by Franco Moretti) characters are nodes/vertices, communications are lines/edges. Moretti uses the techniques of statistical analysis — in this case simple binary counting: do they communicate? Yes/No — to measure interaction between characters. This simple technique permits an understanding of plots as networks of relationships clustered around central hub characters. It is a mode of computational interpretation that both confirms and refutes many of the accepted theories about famous plays.
In other “distant reading” analytic works, Moretti’s team converts entire archives of literature into data in order to reveal patterns that emerge at the macro-scale.
For more info see the complete set of pamphlets of the Stanford Literary Lab.