9. A medium according to claim 8 , wherein the input document comprises an image, and the program code for extracting the plurality of textual tokens comprises program code for detecting a column in the image, optionally correcting the perspective of the image, super-sampling the image, or performing optical character recognition on the image.
8. A non-transitory computer readable medium on which is stored program code for forming a structured document from an unstructured input document, the program code comprising: program code for receiving the input document from a data communication network; program code for storing the received input document in a storage system; program code for extracting a plurality of textual tokens from the input document, each extracted token having a visual style; program code for 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, the first probability distribution comprising a plurality of first probabilities each associated with a corresponding textual class of the plurality of textual classes such that each textual class has one of the plurality of first probabilities associated therewith, each of the plurality of textual classes being related to information conveyed by the textual tokens; program code for applying a context classifier to each token to redistribute the first probability distribution of each token, based on the textual class having the highest first probability of the token's surrounding tokens in context, thereby producing a second probability distribution of the given token with respect to the plurality of textual classes, the second probability distribution comprising a plurality of second probabilities each associated with a corresponding textual class of the plurality of textual classes such that each textual class has one of the plurality of second probabilities associated therewith; program code for applying a visual style classifier to each token based on its visual style and the second probability distribution, thereby producing a third probability distribution of the given token with respect to the plurality of textual classes, the third probability distribution comprising a plurality of third probabilities each associated with a corresponding textual class of the plurality of textual classes such that each textual class has one of the plurality of third probabilities associated therewith; program code for 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 program code for forming a structured document from the plurality of classified tokens in the storage system.