Was there any fundamental reason why Bitcoin crashed today from $680 to $620-630?
Bitcoin is a project created by the NSA in order to take money from the crazy anti-government libertarian movement, by getting them to invest all of their money into the project and then pulling the plug.
The problem is those wacko libertarians then invested not just their money but also their time building more and more services on top of bitcoin and popularizing it into a larger movement. Seriously who builds things anymore? No one in the government foresaw that coming.
Now the NSA is desperately trying to shut bitcoin down, but too many people are supporting the network and more and more people keep viewing every price drop as a buying opportunity, so their attacks are less and less impactful.
At least that is my theory for today's crash, it is as good as anyone else's theory and just as provable as far as I can tell.