ACTION-135: Detail use case for ISSUE-111 (DNT;2)

2012-02-23: Shane indicated that DNT;0 and the existing mechanisms may satisfy his requirements. I close this issue for the time being.

2012-02-24: Re-opened on Shanes request (pending info from Roy/Tom)

Scenario:
- User arrives with DNT;1

I see consensus emerging on the following points:
1. MUST: Publishers need a function to ask for a site-specific exception for all "*" third parties
that it uses (today or in the future). This allows them to work with ad networks and the like.

2. MUST: Users may want to grant a web-wide exception to a third parties (e.g., a producer of a widget)
to make this widget function under DNT;1 all over the web.

3. SHOULD: Other sites (with few and known third parties) would prefer an API where the
third parties are explicitly listed. This allows them to provide enhanced transparency.
This API may not be implementable on all devices (-> only a SHOULD for browsers).

In the call, I'd like to double check that I captured this consensus correctly. If yes, then I'd like to solicit (if needed) updates to the text and then formally close these issues.

I currently believe that this API can also be used for polling.
Open questions (that we may or may not choose to address) are:
1. Transparency for individuals: How can they learn what third parties where actually used by a site?
[Could, e.g., a list be auto-populated one a exception is in place?]

2. Compliance: How to use these functions to satisfy different regulatory requirements?

3. DNT values to signal site-specific preferences. E.g.
1 = no known exceptions for you
2 = "*" exception (sent to 1st party saying that all its third parties are exempted)
0 = You have an exeption (sent to 1st or 3rd parties)
1st: You have an exeption but there is no "*" exception [You may poll for details]
3rd: You either have a web-wide exception or your 1st party got you exempted.