Most web host usually have a privacy policy, I know we do. We would never provide personal information to anyone unless ordered by law enforcement. You really have no control over that unless you have big money to fight the authorities. Some companies may sell there clients information who knows. If they do not have a clearly stated privacy policy obviously they can do so. I would be very weary about no privacy policy on a website where you enter personal information. So in short I am sure some companies do sell this information but no telling how many.