First there's the increase in media attention over the last +-6 months. Bitcoin got some MSM attention when the ECB's report on bitcoin got released and bloggers like Jon Matonis have been talking about it on a regular basis (in his case on a high profile site: forbes). So, even among people who had never used bitcoins before, there was a significant number who knew what bitcoin was or had at least heard of it. People tend to distrust and stay away from new things and we've now reached a point where bitcoin simply isn't "new" anymore for a lot of people.

The reason for the sudden spike: Cyprus. The events there took almost everyone by surprise. There's plenty of people who understand the problems with our "manipulated economy", but even a lot of those had become "complacent". Now that government paper is failing at a faster pace than anyone imagined would have happened in the past year or so, a "sense of urgency" seems to have taken hold of some and they are rushing into bitcoin.