I built a business that lets me live on the beach full time
>  I see articles like this come past on the Internet every once in awhile, and they are invariably received with hostility. "Sampling Bias!" "That guy could only do this because of $X!" "That wouldn't work today in this economy!" "If all this stuff really worked, why tell us about it instead of milking it for millions. He's probably just trying to sell us his book!" Lots of reasons why we should quickly dismiss everything that was said above and carry on the way we were before.Part of me thinks the worst thing I ever learned about was market efficiency. Once you've heard that argument from a professor, you can apply it to just about anything. Heck I even had colleagues use it against me, despite being specifically hired to beat the unbeatable market.The guy in the article is right though, it's bogus. There's lots of little things you can do that might turn into a business. The existing players have not hoovered up all the opportunity, and new opps come along all the time. People talk about things that are profitable even if they haven't locked it all up for themselves.