The WWW is the most popular method of Internet communication. Many of these sites are commercial in nature - they exist to sell goods and services. Transactions are typically carried out by credit card. This is a billion dollar a year industry which is growing rapidly. Find out the vendor's warranty and return policy before you buy.
Some goods are more suitable for electronic trade than others.
Books and electronic equipment are easily and accurately described on Web pages - clothing and art may or may not be as depicted. There are many websites on the Internet that display and sell pornographic pictures. Some of these sites take active measures to assure that pornographic images are not available to children, but many do not. The screening mechanism for determining whether or not the site visitor is an adult is the assumption that if a credit card is available, then the visitor must be at least 21. Many children are clever enough to circumvent the screening methods employed.