1. A method of forming a structured document from an unstructured input document, the method comprising: receiving the input document from a data communication network; storing the received input document in a storage system; in a first computer process, extracting a plurality of textual tokens from the input document, each extracted token having a visual style; in a second computer process, applying a content classifier to the plurality of tokens to produce, for each token therein, a first probability distribution of the given token with respect to a plurality of textual classes; in a third computer process, redistributing the probabilities of each token, based on the classification of its surrounding tokens in context, thereby producing a second probability distribution of the given token with respect to the plurality of textual classes; in a fourth computer process, applying a visual style classifier to each token based on its visual style, thereby producing a third probability distribution of the given token with respect to the plurality of textual classes; determining a classification for each token into one of the plurality of textual classes as a function of the second and third probability distributions; and in the storage system, forming a structured document from the plurality of classified tokens.