The price of Bitcoins surged this week, rising above $9 for the first time in almost a year. The increase suggests growing public interest in the peer-to-peer cryptocurrency.

Last month, we marked the one-year anniversary of the Bitcoin bubble popping. We noted that after plunging for the last six months of 2011, the price of Bitcoin had begun to stabilize around $5. But almost as soon as we published that article, the currency began appreciating rapidly. Today, one Bitcoin is worth about $9.20—a 40 percent increase in a month.