The challenge of walking the marketing tightrope while balancing both ends is at the heart of digital marketing. Any marketer's owned media (websites, apps, social media pages) are on one side, and the ever-evolving needs and perceptions of his target audience are on the other. The work of balancing needs of advertisers and publishers, between CPM (Cost per mile) and CPC (Cost per click), as well as analyzing data and handling privacy concerns, is just the beginning. The options on the market are limitless, just like the list.