Experts write people are taking great risk by offering used hard drives and memory cards for sale. Many people don't realize this but many of the files stored on your drives can still be recovered quite easily, even after formatting.
This way it is possible to recover letters, e-mails, phone numbers, passwords and even online bank accounts from the sellers's storage hardware.
In its test of how good users were at destroying data, Disklabs bought 100 hard drives and 50 memory cards - which included SD cards, flash drives, sim cards and memory sticks - from the auction site.
"Most people made only cursory attempts to erase the data," said Mr Steggles, "and some had not done even that."
During its investigation, Disklabs found large amounts of personal and confidential business data on storage hardware.
Most worryingly, said Mr Steggles, it was possible to extract the temporary files that Microsoft's Internet Explorer browser uses to keep track of what people do when they are using the web.
With a little work, it was possible to reconstruct almost everything that some users did online, and to grab cookies and login details for sites they visited.
Selling your hard drive is quite dangerous as even a couple of formats won't remove all data stored on your hard drive. Sometimes it's even possible to recover data that was deleted months ago. Read more at BBC