Paul Robin Krugman  is an American economist who is currently Distinguished Professor of Economics at the Graduate Center of the City University of New York, and a columnist for The New York Times.

In 2008, Krugman was awarded the Nobel Memorial Prize in Economic Sciences for his contributions to New Trade Theory and New Economic Geography.

The Prize Committee cited Krugman's work explaining the patterns of international trade and the geographic distribution of economic activity, by examining the effects of economies of scale and of consumer preferences for diverse goods and services.

This post is about the Social sites:

The first point, I going to speak of the advantages of the social sites.

You can see what are doing your friends, your family, also you can see what is passing in the word. One point very important is what you can chat with your friend, your family, and you can meet new friends.

The second point, now I go to speak of the disadvantages.

Your privacy it is very important and I recommend it to you change your password one to month. Other they are false persons, they put one photo but they aren't they.

The three point, finally I go to speak about cyber bullying.

Is one bullying in social sites.