First introduced with Netscape 0.9 on October 13, 1994, a cookie is a small amount of text-only data saved on your computer while you browse a certain website. This information can be used by websites to help create custom pages for you upon your return visits or save session information. For example, when you put items into an online shopping cart, cookies allow the host site to save them for when you log back in at a later date.
Are cookies safe?
If you're concerned about web pages gathering information about your viewing habits, you can disable cookies or increase browser security to prompt you before any cookie is created. However, keep in mind some web pages require cookies to be enabled to work.
What is a tracking cookie?
A tracking cookie is one that is used by Internet advertisers and marketing companies. It contains unique information about your computer and browsing history, which is used by the company to deliver advertisements it believes you'd be most interested in viewing.
Another type of tracking cookie is a third-party cookie. These types of cookies are added to a computer by a website or company other than that for which the cookie is used. For example, the cbs.com website has a button for liking them on Facebook. Clicking the Facebook Like button on cbs.com adds a Facebook cookie to your computer. Because the cookie for Facebook came from cbs.com, the cookie is considered a third-party tracking cookie.
Why do anti-spyware programs warn me about tracking cookies?
Because these cookies can track your computer, they can be considered an invasion of privacy. It's up to you to decide if you want to save or delete these files. Apart from the potential privacy concerns, tracking cookies pose no threat to your computer and do not contain malware or viruses.