1. A product.
2. A man who is very fond of the product.
3. A woman who is doubtful of the integrity/usefulness/color of the product.
4. A studio audience that never ceases to be shocked by the power of the product.
Any program possessing these parts is, beyond the shadow of a doubt, an infomercial. Any program that does not have all four parts is either a soap opera, a sitcom or the news.