I've found a similar thing with many forms of social media. My business site gets 500-1000 views a day with a 30-40% bounce rate. Two days ago, we got 5500 views with an 80% bounce rate -- turns out, we got featured on Reddit and were reasonably popular, but people just aren't interested in viewing your site or buying anything, they want to click, see it, be entertained, and move on.