Mobile Devices Hold On to Old Data
Following the directions that come with mobile devices, such as phones and PDAs, to remove data before selling or recycling them is not enough to ensure the next person who holds the device will not be able to see your private information.
Data can still be retrieved from phones that have been reset. A security software company that purchased 10 used smartphones and PDAs on eBay found sensitive, personally identifiable information on nearly all of them.
The company plans to return all the phones to their original owners and has kept all the data it retrieved from the phones on a computer not connected to its corporate network.
Some companies have provided stronger data wiping functions in their newer devices.
http://www.theage.com.au/news/Technology/Software-Can-Resurrect-Cell-Phone-Info/2006/08/31/1156816976190.html
http://software.silicon.com/security/0,39024888,39161863,00.htm
http://www.vnunet.com/vnunet/news/2163176/pdas-sold-ebay-loaded-sensitive