The digital marketer usually focuses on a different key performance indicator (KPI) for each channel so they can properly measure the company's performance across each one. A digital marketer who's in charge of SEO, for example, measures their website's "organic traffic" -- of that traffic coming from website visitors who found a page of the business's website via a Google search.
Using influencers to market your products or services is a great way to quickly saturate yourself into the marketplace, no matter what you're peddling. However, finding the right influencer at the right price is the hard part. You don't necessarily have to go to the top-tier influencers; you can also opt for micro-influencers (those that have 10,000 to 100,000 followers or fans).
Digital marketing is defined by the use of numerous digital tactics and channels to connect with customers where they spend much of their time: online. From the website itself to a business's online branding assets -- digital advertising, email marketing, online brochures, and beyond -- there's a spectrum of tactics that fall under the umbrella of "digital marketing."