Bitcoin, the virtual currency that started as a proof of concept among cryptanalysis buffs and is now garnering attention from institutional investors, crashed today, losing about a third of its value in just a few minutes. You can see the drop in the graph below from MT. Gox, one of Bitcoin’s main exchanges (15 minutes along the x-axis, measured in USD). This crash comes at the end of an incredible rally (graph below, 24 hours along the x-axis), and highlights the biggest concern that many people have about investing in Bitcoins: it’s an unregulated asset with some peculiar characteristics, and…