The main advantage of social media marketing is cost-related. The majority of social media sites are free to access, create a profile and post information. The advantage of reaching your targeted market for little or no cash investment is substantial, and the audience wanting your information voluntarily joins or follows you. Pay-per-click advertisements on sites such as Facebook are "geo-targeted" according to specific criteria, to reach the correct audience. The viral nature of social media means that each person who reads your posts has the capability to spread the news farther within his own network, so information can reach a large number of people in a short time.