An issue of the Windows Secrets Newsletter drew my attention to the potential problems caused by the behaviour of Flash in allowing sites to store cookies up to 100KB in size and then permitting third parties to access that information.
The antidote suggested was the Adobe Settings Manager (which you can only access online!);
http://www.macromedia.com/support/do...manager06.html If it works as advertised, the settings allow you to prevent information being stored (or to delete what is already stored), plus you can prevent sites from trying to access your microphone or camera.