Not efficient compared to what? Compared to online marketing? Or cold emailing? Or talking to random people in the street? I can't actually imagine a more eff

Not efficient compared to what? Compared to online marketing? Or cold emailing? Or talking to random people in the street? I can't actually imagine a more efficient way to get a significant nr of sales from strangers than cold calling personally. Of course contacting people who already know you is better, but the problem for a business is that in most/all cases that list of people who know you is not long enough.