Privacy Seals 'opt-in' or 'opt-out'

A privacy seal is an image that you display on your Web site that is granted by a privacy seal provider. It provides easily verifiable assurance to your customers that you care about their private information.

Take a look at this report from Forrester that does a comparison of different type of privacy seals available. Date of report is September 2006. It also includes privacy seals available concerning the use of children's information.