Then as you browse the site, data is collected as to which pages you visited, how long you remained on each page, the links you clicked, what terms you searched, and so on. After a number of visits to the site, a personal profile emerges. Most claim that they use it to personalize your experience on the site. For instance, if a gardening site learns that you are interested in heirloom vegetables, the next time you visit the site, you might be presented with an article or advertisements for rare tomatoes. But some websites sell this information to marketers, which means that you may find yourself receiving unwanted catalogs from garden suppliers.
Junk mail is more of an annoyance than a serious problem.
But what if you read articles about cancer on a women's health site. Most people consider that an invasion of privacy. Many sites now post their privacy policies online. Before you reveal any personal information, read the policy to make sure you agree with it. Some sites specifically seek your permission to share your personal data with third parties or to receive e-mail announcements.