The process of maximizing the number of visitors to a particular website by ensuring that the site appears high on the list of results returned by a search engine.
Social media optimization (SMO) is the process of increasing the awareness of a product, brand or event by using a number of social media outlets and communities to generate viral publicity.
Those are AdWords ads that a company paid for so that people will notice their business whenever they're searching Google. And, they only have to pay whenever someone clicks on the ad. This is known as cost-per-click advertising (CPC)