What is SMO and SEM?

Social media optimization (SMO) is the use of a number of social media outlets and communities to generate publicity to increase the awareness of a product, service brand or event. Types of social media involved include RSS feeds, social news and bookmarking sites, as well as social networking sites, such as Twitter, and video sharing websites and blogging sites.
Search engine marketing (SEM) is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) primarily through paid advertising.[1] SEM may incorporate search engine optimization (SEO), which adjusts or rewrites website content and site architecture to achieve a higher ranking in search engine results pages to enhance pay per click (PPC) listings.

Search engine optimization (SEO) is a set of strategies with the broad goal of bringing more people to your website the first way, by improving your search engine rankings. Social media optimization (SMO) can be one part of SEO—but it also contributes to all three ways people find you online.
Obviously, SMO has to do with social networks and their growing importance to business. This aspect of optimization deals with enhancing your company's presence and online reputation through interactive communities—not just Facebook and Twitter, but also blogs, forums, and anywhere your business is mentioned or linked to socially.

SMO:
Social media optimization increases the visibility of your social media profiles, your social networking activity and your published content so that it is found by people searching for information and resources that relate to your content. Social media optimization helps drive traffic to your website or blog, makes it easier for others to share with their circle of influence, builds community around your brand and helps search engines index your social media profiles, social activity and blog posts more easily.

SEM:
SMM stands for Social Media Marketing. And as you can guess it involves paid advertising through social media networks. If you are familiar with Facebook ads, then you are seeing SMM in action. It is the process of using paid advertising to broaden your customer reach and increase your brand exposure.