http://www.theregister.co.uk/2008/07...uk_over_phorm/
The way i read this, is by EU law phorm can only profile a person if they give consent. Therefore the only way for phorm to be legal is for people to opt in, in which case they would have a tracking cookie added. If they were to do it the other way & put a cookie on the people who dont opt in, the cookie could get blocked & thier system profile someone not opted in.