At first, the internet was treated as a curiosity. YouTube has a television segment from 1981 on newspapers experimenting with sending digital stories over the phone line. ''Imagine, if you will, sitting down to your morning coffee, turning on your home computer to read the day's newspaper,'' said the host with a bemused smile.

We all know how that turned out. The internet has played havoc with the newspaper industry. It has ripped up the music industry and intimidated Hollywood. What is a curiosity today might be the industry-disrupting, society-realigning, prosperity-enhancing and utterly essential technology of tomorrow.

Two recent innovations suggest the next few decades will be more disruptive than any other time in living memory. Right now, Bitcoin and 3D printing seem the province of geeks and hobbyists. But they're omens of revolutions to come.

Bitcoin is a digital currency that can be used like normal money. You can buy or earn Bitcoins online and use them to purchase goods or services. An increasing number of online retailers accept Bitcoins as payment - including one of the world's biggest dating sites, OkCupid. But unlike normal money, Bitcoins are very hard to trace, extremely hard to tax, and can be completely anonymous. With only a bit of care, you can make it impossible for the government to pry into your Bitcoin account.

Scepticism is reasonable. Bitcoin is an immature technology. It seems prone to huge swings in value, so it's hard to be confident about using the currency in the marketplace. Bitcoin may end up fizzing out.