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