1. A computer-implemented method of identifying named entities, the method comprising: receiving, by one or more processors of the computer, an electronic mail document or a web page document that includes a sequence of terms; calculating, by the one or more processors, a first value representing a coherence of the terms included the sequence; calculating, by the one or more processors, a second value representing an entropy of contexts associated with the sequence; determining, by the one or more processors, that the sequence is associated with a named entity based on: the first value satisfying a first threshold, and the second value satisfying a second threshold; and storing, by the one or more processors, an indication that the sequence is associated with the named entity.