Along the same lines as Paul Krugman's comments, I found this recent blog post from Yves Smith of Naked Capitalism fascinating. Krugman was right that in 2011 Bitcoin's value against the dollar was languishing, but recently it's been climbing pretty steadily for a wide variety of reasons beyond the hard-coded slowdown in new coin production, including concern about deposits in Cyprus, a bug in the Bitcoin code that led to a short-lived panic, and the network effect that comes with more people using the currency.

She goes on to compare Bitcoins to precious metals as a store of value, and talks about whether the current value is a sign of a short-lived bubble or a sign of things to come.

My personal view is that they're really just a niche currency for nerds and people who want to buy pot on Silk Road. I understand why a currency without a central banker appeals to goldbugs and the like, but there's just too much friction involved in converting to and from Bitcoin to make it worthwhile for most people.