According to social psychology,imitation is one of the ways we "learn"(socially and informally)from each other. However, in our daily life,the products we buy sometimes mainly depends on the "celebrity effect".We often hear many parents telling their children that:"Yao Ming drinks the xx milk and he is very tall,so we should buy this milk." It is not rare to see such phenomenons around us and most people share the similar experience. That is why businesses are willing to spend plenty of money on celebrities to make ads for their products.I think this is the best examples of the "celebrity effect". We can see the movie stars or sports stars endorsing products on TV and other medias.
Nowadays celebrity endorsements commodities advertising in recent years more and more common, but also the increasing number of celebrities engaging in false advertisements.
This is the bad side of the celebrity effect that can mislead consumers. However, consumers should be rational to the this effect, never be blind to follow the "live model".