Ghostery

Ghostery is a cost free privacy browser extension for major browsers owned by the privacy technology company Evidon. It enables its users to easily detect and control web bugs, that are objects embedded in a web page, invisible to the user, that allow the collection of data on the user's browsing habits. Ghostery also has a privacy team that creates profiles of page elements and companies for educational purposes.

Blocking
Ghostery blocks HTTP requests according to their source address in two ways: Cookie Blocking and Cookie Protection, which is experimental. When Cookie Protection is enabled, if a cookie is selected from Ghostery's list, it is not accessible to anyone but the user and thus unable to be read when called upon.

In Internet Explorer, Ghostery can detect elements that are not in the page source, such as redirects and iframe contents, but these are detected after execution and cannot be blocked.