"In terms of cryptocurrencies, generally, I can say with almost certainty that they will come to a bad ending. When it happens or how or anything else, I don't know."
"If we have a trader trading Bitcoin, I would fire them in a second ... Its worse than tulip bulbs. It won't end well. Someone is going to get killed ... Its a fraud."
"If I could buy a five-year put on every one of the cryptocurrencies, I'd be glad to do it but I would never short a dime's worth."
"I'm one of the few standing before you...from a large financial services company that has not given up on digital currencies. We set up a small Bitcoin and Ethereum mining operation that now is actually making a lot of money."
The Bitcoin Big Bang is a guide to navigating the uncharted territory of digital currency written by CNBC contributor Brian Kelly.
"Still thinking about #Bitcoin. No conclusion - not endorsing/rejecting. Know that folks also were skeptical when paper money displaced gold."
"I'm not sure I would invest in Bitcoin itself ... but it's here to stay because of the disparity between countries where a monetary system is robust and countries where there is virtually no monetary system."
"People are.... maybe underestimating Bitcoin specifically, because it is like a reserve form of money, its like gold, and it's just a store of value - you don't actually need to use it to make payments."
"A friend sent me part of a BTC [Bitcoin] a few years ago, but I don't know where it is."
"BTC has accelerated much faster than my model assumptions. I now predict Bitcoin at $1 million by the end of 2020."
"Bitcoin is a tool for freeing humanity from oligarchs and tyrants, dressed up as a get-rich-quick scheme."
Chinedu Chiana is an Investor, Entrepreneur, Business & Financial Coach and Author of 'The Smart & Common Sense Investor'. He helps business owners with skills and strategies to create, build and grow profitable online businesses particularly with funnels, social media & email marketing, business automation and marketing advice.