How do advertisers show me custom ads?

Is custom advertising an invasion of privacy?

Understandably, Internet users have shown concern about the tactics used by marketing companies who provide custom ads. After all, these companies gather a great deal of information about millions of different people around the world. Then they use it to place ads that can make it seem eerily like someone's looking over your shoulder.

Much of the controversy surrounds the collection of data using third-party cookies, which can help compile a pretty complete log of a user's browsing history. Critics of this practice fear that such records could be combined with identifying information like names, addresses and phone numbers. After all, who wants the fact that you checked out a list of the top 10 hottest women alive floating around on the Web where grandma might find it? It's highly unlikely that such a thing would ever happen, though: Marketing companies are very wary of engaging in such practices, largely because of the criticism it would attract.

While third-party cookies have drawn some negative attention, most cookies are completely harmless. Some people mistakenly believe that cookies are programs that can plant a virus on your computer or mine your hard drive for personal information. As stated earlier, however, cookies aren't programs, but simple text files that can only be read by the Web site that sent them. Many are used to remember harmless things like your personal preferences for a particular Web site. Even uses cookies!

If cookies and other methods of data collection still bother you, consider this: Revenues from ads allow users to surf many Web sites free of charge. Marketing companies argue that giving up some of your privacy for the sake of advertising is simply the price you pay for this service. Without data collection, ads would be less personalized and therefore less lucrative, causing a loss in revenue that could cause more Web sites to charge for their content. If nothing else, custom ads bug you about something that you might actually want instead of pestering you about something you would never purchase.

If you still don't feel good about all this, you'll be glad to know that you can disable cookies on any Internet browser. This setting is usually found in your browser preferences under the "security" or "privacy" tab. Other ways to limit data collection are more drastic: Avoid performing Internet searches, making online purchases and creating social media profiles. But what fun would that be?