If you've spent any time surfing the Internet, you've seen more than your fair share of banner ads.These small rectangular advertisements appear on all sorts of Web pagesand vary considerably in appearance and subject matter, but they allshare a basic function: if you click on them, your Internet browserwill take you to the advertiser's Web site. But how do they work andwhy are they there?Banner ads are usually relatively simple pieces of HTML code,but their presence on the Web and their importance in Internet-basedbusiness is immense.we'll examine banner ads and their place on the Internet. We'll see howthey work, how advertisers rate their effectiveness, and how you canuse them to advertise your site or bring in revenue. We'll also examinethe technology behind them and look at some of the different forms theycan take. By the end of this article, you will be a banner ad expert!