1. A computer program product being embodied on a computer readable medium for extracting semantic information about a plurality of documents being accessible via a computer network, said computer program product comprising computer-executable instructions for: generating a plurality of tokens from at least one of the documents, each token being indicative of a displayed item and a corresponding position; and, constructing at least one parse tree indicative of a semantic structure of the at least one document from said tokens dependently upon a grammar being indicative of presentation conventions.