24. A system comprising: a memory and a processor; a transaction analysis module stored in the memory and executable on the processor for: retrieving at least one activity record that represents at least one interaction between a visitor and a server-based system; identifying within the activity record at least one input provided by the visitor during the interaction; identifying within the activity record at least one item associated with the input; accessing at least one further activity record containing the input; comparing the activity record and the further activity record; identifying within the further activity record at least one further item associated with the input; establishing a similarity rating of the item and the further item based at least in part on the comparison of the activity record and the further activity record; a synonym recognition unit stored in the memory and executable on the processor, the synonym recognition unit being in communication with the transaction analysis module for: receiving indications of the item and the further item and for receiving indications of the similarity rating; obtaining a document associated with the item and obtaining at least a further document associated with the further item; comparing the document to the further document; determining, based at least in part on the similarity rating of the item and the further item, that the document associated with the item and the further document associated with the further item contain synonyms; designating a term that appears in the document associated with the item as a synonym for a different term that appears in the further document associated with the further item; and a search engine stored in the memory and executable on the processor, the search engine being in communication with the synonym recognition unit for: receiving a search query specifying at least the different term that appears in the further document; and returning, as search results for the search query, the further document associated with the further item and the document associated with the item containing the term that is the synonym for the different term.
38. The system of claim 24 , wherein the synonym recognition unit is for performing at least one thresholding operation that includes comparing contents of fields from the document to contents of further fields from the further document to determine a degree of relationship between the document and the further document.