Page weight is the total size in bytes for all code, content, images and objects that must be downloaded from a Web server to a first-time visitor’s browser. Why is this important? Because page weight is primary factor in Web site performance, and Web site performance is a key factor in retaining users on a Web site.
According to a August 2007 survey performed by Nielsen//NetRatings, 83% of home users in the USA are now using high-speed broadband Internet connections. While that number is growing and the news is good, it still leaves 17% of home Internet users in the USA on 56k or slower dial-up connections. If you have a business that caters to the rural community in the USA, you may want to take notice of the fact that many homes in rural areas still do not have access to high speed Internet connections. They are either too far away from DSL switching stations or do not have cable available to them. Yes, satellite connections are available, but they are expensive and slow. I have yet to see a broadband satellite connection that operates reliably at broadband speeds.
Numerous surveys have indicated that the average threshold or patience level with Internet users is about ten seconds. For every five-second increment over that, larger and larger percentages of users begin to abandon a Web site. If your market focuses on rural Internet users in the USA, can you afford to encourage 17% of your potential market to leave your site without seeing what you have to offer?
You can view Internet connection bandwidth as being analogous to a pipe. The wider the pipe, the greater the volume that can pass through it. If the pipe is too narrow, it will take longer to pass a given volume.
The practical limit if you want a Web page to download and render in a user’s browser in ten seconds or less is 60,000 (60k) bytes. Meeting the ten second mark for a dial-up connection also requires that a user have a good 56k connection, which most users do not have. I have personally seen PCs in farming and rural areas where the connection speed does not exceed 14.4k.
If you think your Web site is performing well based upon your testing, consider whether or not you are using a high speed connection for your testing. If you are, you should consider an independent test. There is a great performance testing tool on Andrew King’s WebSiteOptimation.com site. His performance testing tool is called the Web Page Analyzer. Run your home page through his test and pay particular attention to the section that estimates Download Times. The test results page offers useful advice near the bottom of the page that will help you to resolve performance issues.
Most e-commerce sites will have a very difficult time keeping page weight below 60k. If you display a lot of product images on your Web pages, consider using thumbnails and make sure that each is properly optimized using a good image editing tool. I find that you can stretch the page weight limit for e-commerce sites to about 100k (100,000 bytes), but you will experience significant user abandonment when you venture past this point.
Excessive numbers of images and non-optimized images tend to be the primary cause of excessive page weight. Poorly written or bloated code, especially code with excessive numbers of tables is the number two cause. Excessive database queries–which is common with many free shopping carts–in another problem area.
For a real eye-opener, find an old PC with a 56k or 28.8k modem and view your site through a dial-up connection using this PC. You will then experience what perhaps 17% of your potential customers go through the first time they view your site. For subsequent testing, make sure that you clear the cache in your browser. Browsers cache (store) code and images, which speeds up subsequent visits to a page.
The most important impression is the first impression, so make sure that you are not alienating your potential customers with poor performance.