I believe that, if used appropriately, they can effectively reduce the bandwidth required to transfer a web page. The 30K of graphics used inside a navigation frame will never need to be reloaded as a viewer traverses through your site, and the resulting navigational interface is much easier for a novice surfer to use. Developers often use a large GIF image where plain text would easily suffice. Keep your eyes open for instances where you can replace images with regular text. Using the latest browser capabilities, such as Cascading Style Sheets and Dynamic HTML, you can probably provide the same visual effect for a much smaller toll on bandwidth.
Many sites also highlight sound clips or streamed video.
These can be excellent interactive tools, but do not force them upon the viewer. Then, if the user is interested in pursuing the information, they can follow the link to the sound or video. If not, they can ignore it, saving their time and your bandwidth. Another option for creating low-bandwidth interactive animation or graphics for your site is to use a program such as Macromedia Flash or Shockwave , or Microsoft's Liquid Motion . Keep these guidelines in mind, and you'll be well on your way to creating visually appealing, interactive sites that adapt well to the full range of client and server bandwidth capabilities.