When people talk to each other about positive and negative experiences with products this is called -- promotion.

This concept is commonly referred to as "Word of Mouth" promotion. Word of mouth promotion occurs when consumers share their positive or negative experiences regarding a product or service with others, influencing their opinions and potentially their purchasing decisions. This type of promotion is powerful because it is often perceived as more trustworthy than traditional advertising. People are likely to trust recommendations from friends, family, or online reviews from other customers over a company’s marketing claims.

In today's digital age, social media platforms have amplified the reach of word of mouth, allowing individuals to share their experiences with a vast audience instantly. When consumers have a particularly good or bad experience, they are motivated to communicate that to others, which can lead to new customers if the feedback is positive, or deter potential buyers if it is negative. Overall, the impact of word of mouth on consumer behavior is significant and cannot be underestimated.