Went through the entire opt-out procedure THRICE, and every time I get the message "Opt out requests for 0 participating companies were successfully completed for this browser.", and "Opt-out requests for 134 participating companies were not completed."

I suppose its because they require you to enable Third Party Cookies in order to work, which in turn opens you up to tracking cookies from malicious ad-provider networks that are not part of the DAA. Its just better to install an ad-blocker extension and turn off third party cookies + clear cookies regularly.