Hyperinflation (inverted) looks like this on a log chart, which means it is double-exponential or more:
...Meanwhile we are starting to see curving up on a log-scale chart of BTC price - note how similar the patterns are, with the little bump first and then the huge run up to total collapse of fiat...in fact the two charts align almost uncannily well if you look at the bumps, though of course Bitcoin's chart has yet to complete:![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fkonradsgraf.squarespace.com%2Fstorage%2FMt.Gox%2520USDbtc%2520all%2520time%2520log.png%3F__SQUARESPACE_CACHEVERSION%3D1365215368570&t=665&c=fu-M7ibBc42oUA)
My theory is that regular exponential growth (straight line on a log chart) is from the viral effect of the Bitcoin "meme," while higher order exponential growth - that is, exponentially faster doubling times - is the viral effect + a herd-instinct-based stampede. This latter one is where bubbly-ness can be introduced. However, it seems to still be mild. Here is the best Bitcoin economist I've seen, arguing against a bubble right now:
http://konradsgraf.squarespace.com/blog1/2013/4/6/hyper-monetization-questioning-the-bitcoin-bubble-bubble.htmlOne thing he misses, though, is that the store of value function of Bitcoin is probably the main reason for the price rise now, even though it is ultimately backstopped by currency usage.