I started to think if Google is really disguising AdSense publishers with the conflicting info they have on opting in/out of Interest Based Ads.
In the AdSense panel (My Account tab, Interest-based Ads Preference) they have:
Set your preference for interest-based ads. These ads are served to users...
[Option 1] Show ads based on user interest categories. ...
[Option 2] Do not show ads based on user interest categories. Visitation information from my sites will not be used to help create interest categories.
Setting this AdSense publisher feels like confirmed that his/her sites won't show IBA-s. And this is false and simple misleading! - to say at least.
To see the the truth the publisher has to find they AdSense FAQ, because this is where the reality about IBA-s setting is revealed:
However, you cannot opt out of showing ads to users based on their previous interactions with the advertiser, such as visits to an advertiser's website.
It's hard to believe that the conflict of information on those two pages is simply accidental or due to Google's sloppiness in a matter that affects so many its publisher partners.