Social Media Marketing is one type of sub branch of Digital Marketing where we see many branches well. For example: SEO, SEM, Content Marketing, CMS, E-Mail Marketing, Mobile Marketing etc. There are two types a) Social Media Marketing- It is considered Paid Advertising. b) Social Media Optimization- It is considered Free.
Since we reach the number of users every day by the technology, we should take help from others who are supposed to make our activities better to our business. So that we go for tools which are nothing but software's i.e. e-mail marketing tool for email marketing.