Westlake Village-based ValueClick said today that Jeffrey A. Pullen, the company's COO, has resigned. Pullen had been at the company since 2003 when ValueClick acquired Commission Junction, where he was CEO. ValueClick said that it has appointed Tom A. Vadnais as president of ValueClick, who will work with Jim Zarley, chairman and CEO of ValueClick to handle the responsibility of COO. Vadnais has been at ValueClick since 2001 as a result of the company's acquisition of Mediaplex. ValueClick is an online marketing company that operates affiliate marketing, lead generation, comparison shopping, and other online brands.