The Windows 8 Consumer Preview build has a feature that one person fears is a major privacy concern. On Monday, Infoworld reported that when a Windows 8 PC connects with a number of social networking services like Facebook and Twitter, " ... it keeps a cache of contacts from all of those sources stored on the machine. The cache persists even when the user logs off or the machine is turned off."
Analysts downplay Windows 8 privacy issues - Neowin
Windows 8 contacts cache exposes personal data | Microsoft windows - InfoWorld