Howdy, I've created
another graph showing the recent fiasco.
In the new graph you can see that there was a steady exponential growth for two months from mid-january to mid-march.
Then cyprus went beserk, leading to an immediate and crazy exponential period with a doubling every 11.5 days! To make it clear, this doubling was even faster than the June 2011 bubble. See the linked post for the image showing that.
So, I can offer a hypothesis. When the Cyprus crisis went public, many people thought "Ahh, Cypriots are going to be buying bitcoins, ahhhh, all of Europe will want to be buying bitcoins, ahhhh, the whole world will want to buy bitcoins."
So speculators saw a chance and pushed the price way way up.
I happened to read an article a while ago which stated something like Cypriots, and the whole world, never did go crazy buying bitcoins after all(can't remember where). So this always was (as many many people predicted) just a speculative bubble. I guess MtGox lag and possible DDOS didn't help.
The good news is that we've more-or-less returned to a longer term trend. In fact, if the Cyprus crisis and subsequent bubble hadn't happened, but the Jan-Mar trend had continued, we'd be right where we are now.
For reference, you can also see the long term trend which has been holding since roughly Jan 2011.