An academic study has found that over half of the top 100 websites are retaining user information through Flash cookies without permission.
The study, by researchers at the University of California in Berkeley, will be of particular concern to those who try to delete cookies as a means of keeping their internet browsing patterns private. Flash cookies differ from the HTTP cookies which users are able to delete on request, in that they remain largely undetected by privacy settings on software such as Internet Explorer and Firefox.
The researchers concluded that only a "sophisticated" user with knowledge of the different storage settings for Flash cookies would even be aware of them and be able to manage them. This means that many individuals will be having their privacy breached without their knowledge every time they visit a webpage.
To get rid of flash cookies and stop more appearing instructions are available at http://epic.org/privacy/cookies/flash.html.