Bandwidth reduction will soon be a priority. The proliferation of RIAs exponentially increases the bandwidth requirements of initial page loads, while potentially reducing that of subsequent requests.

• Use public CDNs - both to access and distribute libraries. Public CDNs are built for this purpose and often compres content. If you have your own CDN, use it.
• Use and allow the use of logo images from their original sources. For example, the logo for your product could be displayed, from your server, on many sites. This allows headers to be set for browser caching, such that subsequent requests for the images will be served from the client, not the server.
• Use compression where appropriate. Optimize images and ensure text is text, not images.
• Examine your file and page architecture. Strive to deliver only that content required for each page.
• Check the stats to find where the bandwidth is being used and focus on improving page performance for those pages. Use http://websiteoptimization.com
• Use AJAX.
• Develop locally, use XAMPP or VMWare.