"Flash Cookies, otherwise known as Local Shared Objects (LSOs), are cookie-like data files that are stored on a computer. Flash Cookies are used by all versions of Adobe Flash Player.
Cookies by their design constitute privacy concerns because they store data which may be retrieved by people or programs that are up to no good. Ordinary cleaners do remove regular cookies but do not remove these Flash Cookies, giving the user a false sense of security.
Several services even use Flash Cookies as a data storage to reinstate traditional cookies that a user deleted, which is called 're-spawning'. So even if a user gets rid of a website’s tracking cookie, that cookie’s unique ID will be assigned back to a new cookie again using the Flash data as the ‘backup’. If you value your privacy these Flash Cookies should be removed.
The Flash Cookies Cleaner application was developed to be a small tool that has been designed specifically to remove every Flash Cookie from your system."