While the threat from hackers is low for individuals, a more serious threat to personal privacy comes from companies that operate websites.
Many sites require you to register before you can use their services. Often you must provide personal information, such as your name, street address, and e-mail address. Then as you browse the site, data is collected as to which pages you visit, how long you remain on each page, the links you click, which terms you search, and so on. After a number of visits to the site, a personal profile emerges. The question is, what do site operators do with this information?
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.
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. This is known as "opting in." To avoid this, opt out by checking the "No" box.
If you don't want your web surfing behavior to be tracked without your consent, configure your web browser to reject cookies. A cookie is a small file that is created and installed on your computer's hard drive by a website that wants to collect information about your interaction with the site. As you browse through the site, information is stored in the cookie. The next time you return to the site, that data is transmitted to the site.
Only the site that created the cookie can read it, and it does not have access to other files on your computer. Cookies can be useful for things like storing images so pages will load faster each time you access the site. But cookies are invasive because they are normally set without your consent.
To control cookies when using Microsoft Internet Explorer version 6.0 or higher, go to the Tools menu and select Internet Options. Click the Privacy tab and then select the Medium setting to block third party cookies that transmit personally identifiable information without your consent. Remember to click “Apply” at the bottom of the window so your new settings will take effect.
Clearing Private Data
Your browser allows you to save information such as passwords and browsing history, which can improve web browsing speed or automatically provide information so you don't have to type it in over and over. But you might want to delete that information if you're cleaning up your computer or using a public computer and do not want any of your personal information to be left behind.
To clear any private data on Microsoft Internet Explorer version 6.0 or higher, go to Internet Options under the Tool menu. Under the General Tab and Browsing History select Delete.
Here you will have the option to delete any data saved to your computer by you or by sites you visited.
If you are using Safari on Mac you can turn on private browsing go to Safari and Private Browsing.
And to turn off private browsing simply click on Private Browsing again, and close any windows you've used to view private information.