2016 marketing terminology can be a bit confusing, but there really is differentiation.
Digital Marketing: Digital marketing is an overarching term for the use of digital tools and technology to attract leads and convert them to customers. Activities include search engine optimization (SEO), search engine marketing (SEM), email marketing, social media marketing, display and pay-per-click (PPC) advertising, content marketing and more.
Content Marketing: A subset of digital marketing, content marketing focuses on generating high quality and useful content about your product, service, company or industry. This content is strategically positioned in front of your audience in multiple places, including blogs, social media, promoted posts, bylined articles and more. Content marketing raises awareness of your company, educates your audience, positions you as an expert and drives leads.
Marketing Automation: Also a subset of digital marketing, marketing automation incorporates powerful software and processes to make complex and repetitive sales tasks easier and less time consuming. Primarily an outbound lead-nurturing process, marketing automation delivers hyper-targeted content to your prospects and leads via a series of targeted messages (read more below). A very helpful tool for your sales team, this strategy can be used with your existing prospect list and with inbound leads generated by your digital marketing efforts.