Digital Marketing defined.

Definition of digital marketing: The marketing of products or services using digital channels to reach consumers. The key objective is to promote brands through various forms of digital media. Digital marketing extends beyond internet marketing to include channels that do not require the use of the internet.  

Source: Digital Marketing Definition from Financial Times Lexicon

Viral Marketing Campaigns can be highly successful and are usually arranged through Digital Marketing Agencies.  Check out the following short videos below the second being a highly successful digital marketing campaign run by Art Series Hotel, Melbourne Australia that produced great ROI and global media coverage as explained in the video.

And another highly successfully campaign they ran:

YouTube Video