On social media, consumers are exposed to purchasing practices though peer sent, written messages. Learning through social media includes strategies such as "modeling, reinforcement, and social interaction mechanisms" all at the same time. A study, that focused on peer communication through social media, has revealed that communication between peers through social media is positively related to purchase intentions in a couple ways. First, is a direct impact through conformity. Second, is an indirect impact by stressing product engagement. Lastly, from this study, we learned that consumer-related communication between peers on social media has a positive relationship with product engagement. 
For individuals, social media is used to keep in touch with friends and extended family, network for career opportunities, find people from all over the globe who share a common interest, share content and more. Those who engage in these activities are part of a virtual social network. For businesses, social media is an indispensable tool for finding and engaging with customers, sales, advertising and promotion, gauging trends and offering customer service. Governments and politicians utilize social media to engage with constituents and voters.
Most of what I'm going to list involves sharing sponsored links, although you'll find a few other oddball things in there, too. But sharing sponsored links is where it's at because big brands want to get themselves out there to as many people as possible, and they know people are on social media all.day.long. So yes, they are willing to pay you to help them get their brand/product/message across.
Users typically access social media services via web-based technologies on desktops and laptops, or download services that offer social media functionality to their mobile devices (e.g., smartphones and tablets). As users engage with these electronic services, they create highly interactive platforms through which individuals, communities, and organizations can share, co-create, discuss, and modify user-generated content or pre-made content posted online.