Some businesses are failing to implement email marketing effectively despite the amount of people around the world that use email every day.

Word-of-mouth is a tried and true way to develop a business, and Roku – the maker of a video-streaming device – is learning that email marketing is an effective means of generating word-of-web referrals in a digital age.

MarketingSherpa reports that a recent email campaign from Roku generated 75 percent of the company’s referral sign-ups. One of the leading success factors was including offers and content relevant to email recipients.

The company conducted some research on its target audience. Roku learned that 80 percent of its customers were also Netflix subscribers, and the company used this information to generate an offer that would appeal to its users. The content in email headlines, in the body of marketing messages and on relevant landing pages emphasized the Netflix offer to get readers' attention.

Additionally, the company promoted its referral program in its monthly email newsletter. By positioning referral requests alongside industry-relevant content, Roku appealed to an already engaged audience.

Roku found that the email campaign generated 75 percent of the program's referrals, even though the campaign was also promoted via social media. Additionally, by tweaking message content to give subscribers fresh information about the referral program, the company saw a boost in related conversions.

Developing offers and content for email campaigns will be a competitive necessity this year. A recent report from Aberdeen titled Email Marketing: Customers Take it Personally reveals that 60 percent of businesses will increase their email marketing spend by at least 10 percent this year.