Because for instance think about the Google..! Isn't it earning from the internet..! What about Facebook,Digg,MySpace,Yahoo,YouTube and many more..! They all are earning from the internet and survive because of it..!
So what is the catch..?? Why can't we do it if they can do it?? the reason is innovation..For example Google, one of the biggest companies in the world dominating entire web but back in time it started in a garage Facebook was an idea of an undergraduate..! YouTube and Flicker were small websites which grew to make millions to their owners!
Just ignore the people who are promising to give thousands or even millions of dollars in few days just for paying few dollars and joining their site (which is not going to happen obviously). Instead be open about your environment,about people think what they want and think of some unserved group or part of the community. One important thing you need to remember is do not try to copy others..! Most of the time this will not work newer the idea the better it will be. Once you figure out a way it will give you money 24/7 because internet never sleeps..!
