11. An article of manufacture comprising at least one machine readable storage medium having one or more computer programs stored thereon, the one or more computer programs when executed causing a machine to: order a list of keywords from high activity to low activity, the high activity corresponding to keywords with a statistically significant number of return on investment (ROI) events, the ROI events corresponding to revenue-generating events, partition the list into at least two sets, a head partition including keywords with an activity level above a predefined threshold, a tail partition including the remainder of the keywords in the list, model the keywords in the head partition based on a set of variables, the modeling including generating a revenue per click (RPC) value prediction for each of the keywords in the head partition, the RPC value prediction being based on the set of variables, past keyword revenue performance data, and historical bid density by category for each keyword, score the keywords in the head partition based on the modeling, and cluster head partition keywords with tail partition keywords having at least one common variable into at least one keyword cluster.
16. The article of manufacture as claimed in claim 11 wherein the one or more computer programs when executed causing the machine to generate a revenue per click (RPC) value for the at least one keyword cluster.