I happen to believe that the next gold rush will occur in space, mining the asteroids and the Moon (to get to the asteroids).
However, I can see other possible Gold Rushes in our future and will think about them and discuss them here. If you think of any that I may have missed, I would love to hear from you in comments.
In order to thwart spammers, trolls, and malware purveyors, all comments will be subject to approval before being posted. Sorry about the delay but I believe that we will all be much happier if I keep the comments clean.