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 , the computer program product including 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 the tokens dependently upon a grammar being indicative of presentation conventions .