As consumers become ever more impervious to traditional advertising, marketers are becoming ever more obsessive in their attempts to track consumer habits and target specific ad messages to individuals who will be most receptive to them. At the annual Ad-Tech conference in San Francisco, cutting-edge techniques to ensnare potential buyers comingle with such low-tech ideas as cutting back on the number of ads shown on television. Most intriguing, something called Project Apollo promises to provide greater consumer trackability than ever before, providing what advertisers hope will be a surefire method of discovering which ad campaigns actually work.