All about Cookies.org
Opt-out cookies are cookies created by a website on your browser folder that enables you to block that same website from installing future cookies. The opt-out cookie tells the website not to install third party advertiser or other cookies on your browser.
This prevents the third party ad server from tracking your page preferences within a website or among websites within their network.
The drawback to using opt-out cookies is that they are site specific. They can only block cookies from a specific server and won't block cookies from other websites. To do generalized blocking, you can manage your cookies via your browser's cookie settings.
Many of the biggest third party ad serving companies offer opt-out cookies to users. To find out more, please visit www.networkadvertising.org. It lists networks that offer opt-out cookies and lets you opt out of networks you select.
These are essentially cookies used to avoid cookies. Accepting an opt-out cookie blocks future cookies being installed on your browser by a particular website server or advertiser. It essentially lets you declare that you do not wish to participate in targeted ad delivery, profiling or otherwise have your web browsing tracked. An opt-out cookie will only block cookies from a particular server and is not a generic tool to block cookies from any site you visit. However, you can manage cookies via your browser settings.
The major third party ad serving companies offer web users the ability to accept an opt-out cookie.