Here’s my answer on Quora to the above question:
Word of mouth. Yes, that could be the most effective type of advertising. Why? Because if your friend spoke good about a company’s product/service, you would trust him/her because he does not have any ulterior motives to promote it.
Do you want an example? I am sure you must know about Rolls-Royce, correct? Who does not? Do you know Rolls-Royce has never advertised the company’s product? NEVER. How is it still so popular worldwide? Word of mouth. They make one of the most reliable, luxurious cars in the world. Hope you got the power of word of mouth advertising.
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