Uses

The uses of the popup window are many. There are used by many companies as an effective form of advertising and marketing. For the companies, it is an extremely effective tool because they are able to focus their ads on specific market segments. With proper planning they can hit the desired market segments by using websites they know are used by the consumers they wish to reach.
For example when a user of the AIM service provided by AOL logs onto their account a popup comes onto the screen which is most likely a paid advertisement by the groups represented. One way to look at popups is to think of them as commercials for the internet.
This is an example of what the pop for the AIM service looks like.