Speaking of YouTube.......

[43unite]

The original Firefox extension "Objection" developer quit a long time ago.
http://yardley.ca/projects/project-objection/
I no longer work on the Firefox extension Objection.

The current version is still under development.
http://objection.mozdev.org/
Objection 0.4.0 is under development.
These versions are not for public use. They are here for people who wish to test the latest features.

z12 's suggestion is simple and effective:
In Firefox include the following in user.js to disable window.globalStorage:
user_pref("dom.storage.enabled", false);

IE currently calls it's version of this "Userdata Persistence". This can and should be disabled.

In addition, set your Flash preferences correctly by visiting the settings site:
http://www.macromedia.com/support/docume...nager.html

In Linux you can easily point this garbage to /dev/null forever, and be absolutely done with it.

Not all Flash options can be set by visiting the Adobe site. Unbelievably, Flash permits access to your system microphone and camera (if you have any).

"Applications that are running in Adobe Flash Player may want to have access to the camera and/or microphone available on your computer. Privacy settings let you specify whether you want applications from a particular website to have such access. Note that it is the person or company that has created the application you are using that is requesting such access, not Adobe (unless Adobe has created the application that wants access to your camera or microphone).

If you select Allow, the application can capture what your camera sees and your microphone hears, until you close the application.

The application may want to broadcast the video and audio to other people who are viewing or hearing the application you are running —"

To access these and other setting do the following: while viewing a Flash video right click on the image and select 'settings'.

Blocking all this spyware does not negatively impact Flash performance.