Call for prior art on Patent 8,156,206

The W3C Tracking Preference Expression specification includes the definition of a simple HTTP request header to express a user-determined privacy preference (DNT:0 or DNT:1). The definition of that header provides for the possibility of future extensions to the syntax, but does not define any specific extensions. The Tracking Preference Expression Patent Advisory Group (PAG) is chartered to resolve issues around US patent 8,156,206 in relationship to this technical approach.

The PAG seeks information about preference expression methods (privacy or otherwise) that were available before February 2007, and provide evidence of prior art that would help to resolve the patent issue at hand.

By making this call, neither the DNT PAG nor the W3C make nor imply any comment whatsoever on the relevance or validity to the DNT Working Draft of claims related to the patent at hand.

Feedback should be directed to the PAG's public mailing-list: public-dnt-pag@w3.org. Private feedback should be directed to the PAG Chair: Rigo Wenning (rigo at w3.org)


The holder of patent 8,156,206 approached a number of participants in the W3C Tracking Protection Working Group about the possible relevance of this patent to the DNT header's technical design. After an initial attempt to secure royalty-free licensing failed, W3C established the Tracking Preference Expression Patent Advisory Group. In subsequent conversations, including as a result of a discussion with the PAG, the patent holder again declined to make essential claims, if any, available on a royalty-free basis according to the W3C patent policy.

W3C established the Patent Policy with the goal of producing Royalty-Free Specifications. In accordance with the exception handling procedures of the policy, W3C launched a Patent Advisory Group (PAG) to determine a possible response. A PAG may reach a number of conclusions, including advising W3C to search for prior art.

About the Tracking Preference Expression DNT PAG (DNT PAG)

The Tracking Preference Expression Patent Advisory Group (DNT PAG) is chartered to study issues and propose solutions around US patent 8,156,206 in relation to the Tracking Preference Expression (DNT) Working Draft.

Rigo Wenning (W3C) is Chair of the PAG. The W3C Staff Contact for the Tracking Preference Expression PAG is Nick Doty.

The PAG advised W3C to issue this public call for prior art.


What is the goal of this page?

The PAG is using this page to collect links and references to technology that may help to circumvent the patent, or clarify the relevance of the patent's claims to the Tracking Preference Expression specification. This information may be useful to help the Tracking Protection Working Group to allow for a Royalty Free Tracking Preference Expression Specification.

Does the holder of Patent 8,156,206 participate in the PAG?

The holder of the patent does not participate in the Patent Advisory Group. The PAG invited the patent holder to participate in one meeting.

Does Work on the Tracking Preference Expression Specification have to stop now?

No. The work on the Tracking Preference Expression specification can continue in parallel to the Patent Advisory Group. Nevertheless, the Tracking Preference Expression specification will not be able to enter the status of Proposed Recommendation as long as the PAG is running.

Does W3C believe that the '206 patent is essential to the DNT specification?

The formation of the PAG and this call for prior art does not constitute any statement by W3C or the PAG on whether or not the '206 patent contains claims essential to the DNT specification.

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