Social networking sites such as facebook,twitter,orkut etc are used largely by teenagers. Where they can find new friends and expand their social network..it is also a means of fast,effective and cheap communication system.it allows us to share our ideas and view points with multiple individuals at the same time

According to Lionel Robbins in the work he published in 1932 "Nature and Significance Of Economic Science"   "Economics is defined as the science which studies human behaviour as a relationship between ends and scarcity means which has alternative uses"....its considered as the most scientific definition of the whole lot in Economics