Opt-in requires the collector of information to request permission from the consumer. Opt-out allows information to be collected and the consumer must find out who is collecting the information. Only two types of information collectors exist, those who interact with the consumer, such as a Web site, and those that do not interact with the consumer, third party information collectors. Web sites that interact with a consumer are beginning to police themselves and request opt-in from consumers. This is not difficult for the site since the consumer is interacting with the site and is given a choice.
Third parties are the major issue.
They currently cannot. This is the only difficult issue and the one issue that will be very hotly debated. You must look at the Web page code, then find the advertisement server, go to their site, dig through their pages and locate the opt-out page. Third parties are scared to have consumers first opt in, since they have no way of communicating to a consumer when their ad appears on a site. Both can win, and both must win for the free content and lower priced products to continue to flow like a fire hose on the Internet.