I'm not so sure the term "bubble" is a good one.
Since Bitcoin is so many things - currency, commodity, payment system, protocol, internet money - you can't make direct comparisons with say; the real estate market or the gold and silver markets.
IMO Bitcoin has several of the qualities of an Internet startup company with new/revolutionary technology. And some startups just keep gaining value until they are multi-billion dollar companies...
The fact that valuation is rising fast does not necessarily imply that there is a bubble.
One of the best analyses presented on this so far.
If you think this is going to act anything like the stock market, think again. I have been investing actively in the stock and options markets for over 20 years. I have never seen anything like what Bitcoin is doing. The forces acting on it and the nature of how it is bought and sold are entirely different and totally astounding. Some serious players are getting down with Bitcoin right now. I am constantly talking the back channels. The big money managers are going to be taking over the place soon, and that's when you will see the serious money. It's chump change right now.
Maybe it's just we have got a lot of working class miners out there that are not really experienced in finance. Not sure. But it seems to me that the market has been owned by amateurs up until now. These price multiples you are seeing are like raw ribeye in front of Lions. I'm lecturing some investors this month, with millions of dollars mobilized and they are ready to dump out of USD pegged plays. They want me to show them how it works and how to buy in. And I'm just one solitary fella. Every one I have told about the bitcoin market has pretty much gone bananas.
We are seeing an evolutionary progression from a nerd-owned system (no offense, im quite a nerd too) to a pro-owned and "everyman" owned system.
I highly exhort you to think about Bitcoin differently than what you may already think you know. It's not a stock. It's not a bond. It is entirely new and different, drastically different than anything that has come before.