The media giant’s search marketing business wants to be numero uno in the field it helped create. Yahoo Search Marketing’s getting an extreme makeover. Earlier this year, Yahoo re-branded its online marketing unit. What was once called Overture became Yahoo Search Marketing in a move to more closely identify the group with its corporate parent. Next step: the unit moved from Pasadena, California, into fancy new offices in Burbank, California, home of Walt Disney and other high-profile media companies. Its executives are launching an aggressive assault to regain some ground lost to search leader Google in an area they had...