The very first law in advertising is to avoid

   the concrete promise  and cultivate

             the delightfully vague.”            

Well i think Bill cosby is rigth with this idea about advertisements. What advertisements try to do is to make people know about the good things about the product that it is trying to sell, and advertisers know this. They understand the people's mind and they know how to persuade us to use any product or service. I understant this idea like this in which advertisers will show the good part of everything and they will hide everything not okay, the price, the quality, etc. You will never find an advertisement that could say thet the quality of the product is not good or thing like that. Another way to understand this is the simplicity of a tipical advertisement, it shows the delighfully vague, i mean, not so many words, and it will avoid the concrete promise, never promising something special to the target group