Many website operators produce income by selling advertising space on their sites. Advertisers will pay a premium for ads that are more likely to reach their target demographic. In other media, such as broadcasting, advertisers engage in targeting by purchasing advertising time during programs that those who buy their products are most likely to watch. The Internet presented new challenges and opportunities for advertisers, because, rather than aiming their ads at groups of people who visit a particular site, their ads are aimed at the individual user. This maximises the odds that the user who sees the ad will be interested in the product or service it touts. This book explores today's current issues in Internet advertising and sales.