Jason Fitzpatrick:

A whopping 40% of the used hard drives on eBay contain easily recoverable personal data. Use the following guide to ensure your personal data never makes it out into the wild. Photo by AMagill.
Kessler International, a computer forensics company from New York, conducted a study of used hard drives available on eBay. Almost half of the hundred drives they sampled, purchased in random bulk lots, contained data that was easily recovered. A shocking amount of them required no more recovery effort than plugging them in and powering up. They found personal photos, financial records, emails, personal and corporate correspondence, corporate secrets, and more: