14. The method of claim 13 , wherein generating a node signature vector that represents a node of the taxonomy comprises: for each of the aliases of the node, generating an alias vector representing the alias; and combining the alias vectors to obtain the node signature vector.
15. The method of claim 14 , wherein generating an alias vector representing an alias of a node of the taxonomy comprises: communicating the alias as a query to a search engine; accessing one or more search results returned by the search engine in response to the query; and calculating a value for each of the tokens based at least in part on a first number of appearances of the token in the documents and a second number of appearances of the token in the search results, wherein the alias vector comprises the values calculated for the tokens ordered according to the token order.