Testimonial
A testimonial is when a company uses a celebrity or famous person or a member of the public to endorse a product so the consumer wants it too. For example a professional football player recommends a particular brand of shirts. The idea behind this is for the consumer to think "Oh! That famous person likes that shirt, I think I'll get it too!".
Testimonial Media
An advertisement for the Wikimedia Foundation incorporating a series of editor testimonials
Actress and model Lin Chi-ling at the LG New Chocolate Phone launching event for the BL40, 2009, Hong Kong
Pope Leo XIII endorses "Vin Mariani", a patent medicine containing cocaine