Everyone is saying that Javascript is the world's most popular language, or at least soon will be.
That saddens me as I do not care for it at all. It's not like I can't learn how to code in JS, but to do so I find quite unrewarding.
I don't see 3D printing being commercially interesting for at least another few years. For anything you really seriously want a custom-made part for, you'd want a metal part made by an experienced machinist with a CNC mill. I expect 3D printers will get there someday but not soon.
Drones, quite likely there are many uses for them other than snapping pictures of white house lawn.
Bitcoin, maybe. In the long run, definitely. There is a specific limit to how many bitcoins can ever be mined. At the same time, more merchants are accepting them. Without a doubt, the dollar price of a coin will increase. I do not know yet - I haven't really checked - whether i'd expect bitcoin to do better than what I could do by investing in stocks, bonds or commodities, but in the long run I expect they would do better.