Firstly, SEO is a set of strategies with the main purpose of bringing as much traffic as possible to your website. SMO also converges with SEO's purpose, therefore it can be part of a SEO.
Clearly, SMO has to do with social networks . It deals with enhancing your company’s presence and online reputation through interactive communities (Facebook, Twitter,blogs, forums, streaming..) and anywhere your business is mentioned or linked to socially.
SMO can contribute to strengthen your brand and boost visibility, as well as generate leads and increase sales. In order to improve your SMO for your small business, you should focus on engaging with relevant social audiences, contributing to conversations, and posting your own shares. Say you write a good quality threat in a related subreddit and interact with the people commenting about it. That's a good example of a SMO.