ACTION-98: Bring input on ISSUE-111 to the group; otherwise it's closed

Description:
Should the user agent send a different DNT value to a first party site if there exist site-specific exceptions for that first party? (e.g. DNT:2 implies "I have Do Not Track enabled but grant permissions to some third parties while browsing this domain", DNT:3 implies "I grant you a web-wide tracking exception")

Response:
<non-normative>
To better arm Publishers with the ability to distinguish between users who have a general DNT signal activated (DNT:1) and those who have also provided for a Site Specific Exception for their site, it would helpful for a different signal to be provided in the later case.  This approach will help reduce site-specific exception list queries, as well as, allow for a cleaner site-specific exception process on "first use" scenarios.

<normative>
Where available, User Agents SHOULD provide 1st parties with a distinguishing signal to alert them that Site-Specific Exceptions exist for the 1st party.  If a User Agent supports this functionality, it must reply with a DNT:2 signal when appropriate.