Crystal O'Neill presented a case study on mobile advertising tests conducted for a psychic business. The initial test using regular landing pages performed well, while a dedicated mobile site led to higher costs. Adding phone extensions to the mobile site lowered costs. The most successful strategy was directing mobile users to call directly, lowering costs by 22-29% compared to desktop. The key lessons were that mobile sites don't guarantee success, regular landing pages can work well, and mobile users prefer calling over other interactions. Extensive testing of different approaches is important to identify the most effective mobile strategy.