Abstract: A method of updating electronic mails (emails) data dataset that comprises providing a dataset which comprises a plurality of previously identified original message content blocks as a plurality of discrete units, each the original message content block having a header content and a sender content and being extracted from emails exchanged in a multi-email correspondence, receiving at least one additional email, analyzing the at least one additional email to identify a plurality of original message content blocks, tagging each of the plurality of original message content blocks as a discrete unit, and updating the dataset with the plurality of original message content blocks.