What is digital marketing? According to Wikipedia, it is:
"Digital marketing is the marketing of products or services using digital technologies, mainly on the Internet, but also including mobile phones, display advertising, and any other digital medium."
It's really any marketing activity you do electronically. Sending an email advertising a product, a service or an event is considered marketing. Placing an online ad on a website is part of the marketing strategy. Using Social Media, like Facebook, Instagram, Twitter to advertise your service or product is digital marketing.
To be successful in your digital marketing, search engine optimization (SEO) must be part of your digital marketing plan. Ranking highly on search engines must be a priority otherwise, you might as well throw your money away.