Final answer:
Typography is the subject of the question. More than two typefaces in an ad can have a negative effect on the ad because it reduces visual consistency.
Step-by-step explanation:
The subject of the question is Typography. Typography refers to the art and technique of arranging typefaces to make written language readable and appealing. It plays a crucial role in graphic design and advertising by conveying meaning and creating visual interest.
In the context of the question, more than two typefaces in an ad will likely have a negative effect on the ad because it reduces visual consistency. Using multiple typefaces can make the ad look cluttered and unprofessional, reducing the overall impact and effectiveness of the design.