Buy a second-hand hard drive on eBay and you could be thanking its previous owners for more than just the memory.
Security researchers at BT labs found that more used hard discs were stuffed with sensitive corporate and personal information than in its tests a year ago.
Two thirds of the drives bought second-hand had not been wiped properly, exposing their original owners to identity theft and worse.
Last year, by contrast, 45% of users seem to have got the security message.
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"A significant proportion of the disks examined still contained considerable amounts of information, much of which would have been of a sensitive nature to the organization or individual that had previously owned the disk," say the researchers.
They recommend that anyone selling or giving a computer uses 'shredding' software to delete all traces of their data, rather than just deleting files in Windows, say, which can leave the underlying information intact.
The researchers intend to publish their findings in the International Journal of Liability and Scientific Enquiry, just as soon as they've nicked enough cash to fund a couple of Caribbean holidays, blackmailed some judges and deleted four hundred millions of dressed-up pets and lame parties.