3. The method of claim 1 , wherein the step of automatically merging the first and second extraction rules is performed in response to a programmatic determination that at least a predetermined degree of correlation exists between the first and second extraction rules.
4. The method of claim 3 , wherein the first and second extraction rules are generated using structural graph representations of the first and second markup language documents, respectively, and the method further comprises calculating the degree of correlation between the first and second extraction rules such that different non-zero amounts of weight are given to different nodes of said structural graph representations.