Every business person, whether on a dusty street in the Middle East or in an air-conditioned high-rise in New York City, has to convince the buyer that his product is the best and that the buyer would be missing out on a great deal by walking away from the transaction. The object of the person or company selling the goods and services is to convince the buyer that he will get more than he is being asked to give.
People have been mastering the art of selling products and services to those who need them since the beginning of time. The methods that entrepreneurs use to sell their goods have changed down through the millennia, but the principles are still the same.
Granted, the method of selling online is relatively new in the history of commerce, and there are certain unique strengths and weaknesses related to online commerce that did not come into play just a few years ago. Selling online is still selling, and the principles have remained unchanged down through centuries of business transactions.