Some of the dumbest ideas are the biggest. Strangers driving you in their cars? People turning their spare rooms into hotel rooms? I wouldn&#x27;t have believed (or invested in) either of these ideas.<p>My favorite example is YouTube. If you had asked me if I wanted to invest in a video upload site where 95% of the material were pirated clips off of TV I would have said &quot;you&#x27;re crazy! You&#x27;ll be sued out of existence.&quot;