Some companies which set cookies through their ad servers offer the opportunity for web browsers to accept a 'zero' or 'opt-out' cookie. Accepting an opt-out cookie prevents any 'unique' data relating to your browser being processed by that server.

Opt-out cookies allow you to choose not to participate in personalised ad delivery, profiling or to have your browsing tracked by a particular adserver. If you prefer not to receive personalised advertising from AOL, which is based on your web site visits on AOL’s network, you can opt out of this service. Note that if you accept an opt-out cookie you will need to accept it again each time you buy a new computer, change web browsers or delete this cookie

Accepting an opt-out cookie will only affect cookies from a particular server and will not block cookies from any site you visit. If you wish to disable all cookies you can do this by adjusting the setting on your browser, but remember that you may not be able to access all the interactive features of the AOL Web Services.

If you want to prevent a third party ad server or ad network provider from sending and reading tracking cookies on your computer, you must visit each ad server or ad network providers’ web site and opt out through their respective privacy policies (if they offer this capability). Click here to see the list of companies whose ad servers may set cookies on your browser. You may also access the opt-out links of many ad servers at www.networkadvertising.org.