There’s a lot of talk lately about social proof (or social influence). According to Wikipedia, social proof is “a psychological phenomenon where people assume the actions of others reflect the correct behavior for a given situation…”. Many influential bloggers prominently display numbers such as their Alexa rank, their Klout score, the number of followers they have on Twitter and how many Facebook fans they have (and much more).
Social media plugins can be effective marketing tools to demonstrate approval. This sort of “social proof” can help influence customers.