I was testing some sites with a P3P validator and it says that:
Sex.com does seem to be compliant:
http://validator.w3.org/p3p/20020128...www.sex.com%2F
Yahoo.com isn't compliant:
http://validator.w3.org/p3p/20020128...www.sex.com%2F
You can check URL's here:
http://www.w3.org/P3P/validator.html
Assuming that the tool actually works, someone should run the list of all the major adult sponsors and see who comes up P3P valid and who doesn't.