Effective banner design starts with recognizing the limitations of the tools that will put your ad in front of your audience: browsers and Internet connections. Unless you are targeting a highly specialized niche market (such as Web developers), you'll want to design a banner ad that is fast to download and easy to view on the most common connection types and browsers. Use this checklist to determine which banner ad technologies are appropriate for your intended viewer.
Browsers Currently, the browsers most widely used are Microsoft's Internet Explorer and Netscape's Navigator or Communicator. Though many Web sites today are geared to versions 4.0 and higher for both companies' products, it's important that you consider the viewing limitations of earlier versions - and of lesser-known browsers such as Opera or Mosaic - when creating your banner ads. Since the idea behind most advertising is to reach as wide an audience as possible, you don't want to leave out users who might not be using the latest browsers. You can avoid making this mistake by testing proposed banner ads on the browsers that are most likely to be used by your target audience.
Connections Broadband technology is being heralded as a solution to the "fat data, skinny pipe" dilemma, the phenomenon that causes site slowdowns and crashes when Internet connections can't handle the amount or size of the data moving from server to browser. But broadband is a long way from widespread implementation, so until then you're much safer assuming that your target audience uses a typical connection. For most Web users, that means a dial-up line (through a modem) at speeds no greater than 56 kilobits per second (Kbps), with 28 Kbps being even more realistic. Again, testing with the least sophisticated connection type is the best way to ensure that your ad can be widely viewed.