Digital marketing is the art and science of marketing over digital media.
It is a rapidly developing space. What started as banner ads on web sites and emails is quickly moving to use big data analytics, tracking software, and many other tools.
Activities such as search engine optimization and search engine marketing have almost become industries in themselves and have spawned many instant experts.
Other forms of digital marketing are being built across social media platforms.
The technology behind Facebook and Google are built to deliver results based marketing. Putting the relevant marketing messages and advertising in front of people based on their online behaviour and preferences.
According to wikepedia 4.5 trillion ads are served online annually.
According to the Internet Advertising Bureau UK, the 2015 full year digital adspend was £8.606bn, 51% going to paid for search, display 35% a