18. The system of claim 15 , wherein the active learning module is further configured to: receive an indication of relevance from the user of at least one term of the second subset; and adjust the model based on the received indication of relevance of at least one term of the second subset.
19. The system of claim 18 , wherein the active learning module is further operative to: receive a third plurality of semantically related terms from the keyword suggestion tool; and select a third subset comprising at least one term of the third plurality of semantically related terms based on the adjusted model and one or more properties of the third plurality of semantically related terms.