Cookies have information that identifies the user, for example: login or username, passwords and shopping cart information. When a user revisits a Web site, the computer automatically "serves up" the cookie, which launches the user's identity and there is no longer a need to re-enter the information. Then they use that information to send them advertisements relevant to the time of day or personal information. A coffee company, for example, would place coffee ads early in the morning so the user will think about coffee and go out and buy that brand.
Advertising agencies keep their clients information on a database. Any information about the user, can be found by searching for specific data about the user. The database will then return your search with the clients that contain this data.
Interactive online advertising greatly personalizes advertising. It is a two-way communication between client and agency where the person is actively engaged in the process. The advertising agency uses Internet tools such as pop ups and emails to catch that person's attention. This includes fixed and mobile e-mail, Worldwide Web (WWW), messaging, other mobile services.
Junk mail was customarily used by advertising agencies to send out advertisements to many people and wait for a response. Generally only 1% - 2% would answer these mails . Agencies then started setting up databases and statistics and monitoring them to find out how they could save money and time to send out advertisements more effectively. Over the years they realized that the more direct and personal the advertisement was, the more people would answer and the more effective their advertisements were.
This new way of advertising has become a trend and Agencies have now started explore their horizons by sending personalized emails to PDAs, cell phones and home computers, creating the illusion of a personalized email. This method has become more popular over the last 3 or 4 years and will lead to being the most popular way of advertising for companies.