sion. They also provide a great deal more information about who's viewing them than either television or billboards. Advertising on the Internet-particularly video ads- are often better able to hold the attention of viewers by being entertaining, brief, and interactive. These ads can ask people to fill out a survey in exchange for being entered into a contest to win a prize. Electronic Commerce The Attraction of Online Services Online services provide convenience. People can access them at any time of day and from anywhere they have a broadband wireless or wireline Internet connection. Web site owners can also enhance their sites with photographs, video, and links to other locations. Eye-catching, easily navigated sites that attract large numbers of people are a draw to advertisers, and thus earn more revenue. Social Networks Social networks have materially affected how people socialize. In general, people make fewer telephone calls. Instead, they often stay in touch and keep others posted through social networks, Twitter, and e-mail. In particular, they can stay in touch with friends and family in other cities and countries. A quick message on Facebook is all it takes to keep people current on personal news. While e-mail also lets people stay in touch regardless of distances, social networks are more suitable for updating larger groups of friends simultaneously. They are also used to exchange information about travel and shopping, and to share experiences with others. Relatives and friends update one another through photos and videos uploaded to social networks. This is a powerful draw and one reason why social networks, origi- nally used only by college students and teenagers, have grown SO quickly. Photos, and in particular video uploads, provide a way for grandparents, relatives, and close friends to feel close to children as they grow up. Examples of large social networks include Facebook, LinkedIn, Baidu in China, Orkut in India, and Friendster in Asia and the Pacific islands. Other social networks are esta