Ask anyone what cryptocurrency is and they might give you a funny look, scratch their head and give some sort of lopsided explanation about money in the ether. I likely can’t do much better, but it’s currently all the talk, and that might be a bad sign...the fact that EVERYONE is talking about it and not just shrewd and educated investors. So...what is it? From Bitcoin's website:Bitcoin uses peer-to-peer technology to operate with no central authority or banks; managing transactions and the issuing of bitcoins is carried out collectively by the network. Bitcoin is open-source; its design is public, nobody owns or controls Bitcoin and everyone can take part. Through many of its unique properties, Bitcoin allows exciting uses that could not be covered by any previous payment system.Got it? Kinda? Think no banks, no tendered currency, no governments printing money, just trading services and products between people using digital money online - Bitcoins. You can get set up to be paid in Bitcoin and buy things with Bitcoin, although not everywhere accepts it of course...in fact, precious few places do.It sounds futuristic and some believe this is where global economies are headed...and fast. Bitcoin has seen stratospheric growth over the last year and each ‘coin’ is now over $10000 in value, most of that in the last year. It’s a far cry from the less-than-8-cents per coin in 2008. That kind of exponential growth, however, should raise a concerned eyebrow when it comes to investing. Most reputable brokers and investment firms won’t touch cryptocurrency from an investment perspective. They feel it’s too volatile, lacks government oversight and is the very definition of a bubble. Others believe it’s going to hit 100,000 per coin in the very near future and maybe even more. Remember I mentioned EVERYONE is talking about it? That kind of discourse is a hallmark of a bubble, as is exponential growth as EVERYONE jumps in without looking.The crime element. There is concern over the potential criminal element involved in cryptocurrency. Without centralized banks or government oversight, what is stopping large criminal organizations from switching to cryptocurrency to ply their underworld trades? The Ontario Teachers Pension, one of the largest in Canada, won’t touch Bitcoin as an investment claiming there is a ‘ton of drug money’ involved. Take that sentiment one step further and watch a Bitcoin-funded terrorist attack either make governments jump into action, or stop people from buying it altogether. It really has the potential to be that volatile. Even Russian President Vladimir Putin wants it banned citing risks of money laundering, tax evasion, and terrorism.Here what some seasoned investors have to say:Warren Buffett has said, "it's a mirage basically." JP Morgan CEO Jamie Dimon has said it's a "fraud" that will eventually "blow up." US billionaire Mark Cuban has advised only to invest if you're prepared to lose your money. Former Fortress hedge fund manager Michael Novogratz tells CNN, "I think this is going to be the biggest bubble of our lifetimes by a longshot."In the meantime, those who have Bitcoins are seemingly getting rich literally overnight. It really is hard to say where cryptocurrencies are headed, but if the experts are saying be very careful, you might want to lend an ear.