I found this article about myths in the digital marketing space, written by Steve Surman. It's interesting to read about his views on how you should develop a brand strategy that engages customers, which includes digital marketing, but isn't defined by it. Digital is a channel that you can use to engage customers, but isn't the necessity in all cases. Not sure I agree with everything he states, but I always like to read about various views by experts out there. Check it out! 
http://www.dmnews.com/the-10-biggest-myths-in-digital-marketing/article/318838/