Customer satisfaction is about how happy a company's customers are with it's products and services.
There are many things that a company does that can factor into customer satisfaction metrics:
When customers are unhappy with a company, they don’t just sit and simmer over their keyboard. They post on Facebook. They complain on Twitter. They tell everybody who is willing to listen.
On the other hand, happier customers are more loyal and become advocates for the company. They ultimately help the company find even more customers.