The Digital Advertising Alliance explains why it’s quitting the Tracking Protection Working Group:

Despite extension after extension of its charter year after year by the W3C, the TPWG has yet to reach agreement on the most elementary and material issues facing the group. These open items include fundamental issues and key definitions that have been discussed by this group since its inception without reaching consensus, including:
· Defining a harm or problem it seeks to prevent.
· Defining the term “tracking”.
· Identifying limitations on the use of unique identifiers.
· Determining the effect of user choice.

Yup, that’s right: after two years, the group still hasn’t defined tracking!

Read the unfolding exchange on the W3C’s public listserv, and for more context check out “Do-Not-Track on the Ropes as Ad Industry Ditches W3C” in AdAge.