The bottom line is that this is how they make the most money. But having plastic is far from proof that a visitor is an adult. COPA's detractors point out that kids can borrow or steal a grown-up's credit card. They add that some young people have their own credit cards, guaranteed by their parents. It's too time-consuming.
Instant access is the key, because porn is an impulse buy.
Of the dozens of adult verification systems on the Web, most require subscribers to fill out an application form that asks for a credit card number. Some sites purportedly accept birth certificates or other documents as proof. Tantalizing pictures, hinting at what the subscriber potentially will be able to see, provide the incentive to complete the form. Subscribers then receive a password that allows them access to certain Web sites. Critics of adult verification systems claim that the sites are more interested in producing revenue than screening out minors, and that some of the services overcharge subscribers to boot.