Just take those annoying spam emails that promise a fortune in some penny stock. Believe it or not, researchers have found a large number of investors actually follow the recommendations contained in the spam. One study by Laura Frieder of Purdue University and Jonathan Zittrain of Harvard University, found that the stocks mentioned in those otherwise annoying emails experienced a huge price increase, as well as a big jump in volume, after the messages were sent. Clearly, investors’ skepticism is being trumped by an eagerness to believe. As Zittrain told me: “Greed all too easily colors our objectivity,” and this is true for all types of investors.

Source: Why the Twitter hoax suggests the stock market is near a top – MarketWatch