For me Bitcoin is surely not a bubble as we have already seen much drops in the prices of Bitcoin and other crypto currencies and also their are many examples of very rapid rise in the rates of some coin so we cannot say that it is a bubble as a smart investors will now buy more coins as it is a great opportunity for every one to become rich very easily.
Here is the story I tell new traders.
Isaac Newton was one of the smartest people to ever live.
"Back in the spring of 1720, Sir Isaac Newton owned shares in the South Sea Company, the hottest stock in England. Sensing that the market was getting out of hand, the great physicist muttered that he '
could calculate the motions of the heavenly bodies, but not the madness of the people.' Newton dumped his South Sea shares, pocketing a 100% profit totaling £7,000. But just months later, swept up in the wild enthusiasm of the market, Newton jumped back in at a much higher price and lost £20,000 (or more than $3 million in today's money. For the rest of his life, he forbade anyone to speak the words 'South Sea' in his presence."
So if one of, if not "THE" smartest man every to live cannot avoid a bubble, how are you going to avoid it? (really not looking for an answer to that question). I've lived through a lot of them, traded them, and hated them all. No one ever knows what a bubble is until it's pasted. Just the way it is. But you need a trading strategy to deal with market moves like a bubble popping or correcting or pausing, or what ever you call hitting $20,000 and pulling back to $7,500.