Contributor(s): David Germano
It is best to make a web site as fast as possible, which is crucial for accommodating different bandwidth scenarios.
The speed of access to a web page, and web site overall, is determined by many factors, but much of it has to do with the size of the pages in question, and the way specific processes are implemented. A good set of guidelines for speeding a site up can be found at: http://developer.yahoo.com/performance/rules.html
The overall size of a page is determined by a number of factors, of which the actual text is rarely an important component. Most important is the java script, images, graphic icons, and videos. There are many tools allowing you to see all of the distinct files a webpage calls so you can asses your own pages, plus compare them to other pages on the web. One such tool is this Add-on in Firefox - add it, and then just right click or use the Tools menu to see https://addons.mozilla.org/en-US/firefox/addon/2214.
There are other utilities to measure loading speed that we can use to chart our progress on speeding the site up.
Images have dimensions – how many pixels long and wide – which determine their size on the page, but for viewing speed what is more important is their file size – measured in terms of KB and MB. To view both in Firefox, for example, right click on an image and choose “properties”.
A typical thumbnail should be sized around 10kb.
It is especially important to slim down pages where new users will first land. You want them to have a snappy experience on those pages initially, even if subsequent pages dense with content might be slower - at that point users have more commitment to stay with teh site. For those pages, it would be best to have 100k or less.
A typical page should be no bigger than 300 kb.
In Production, it is best to compress Java script.
With Ajax you may have heavy frame, but that may be ok since it is persistent and not loaded repeatedly. Thus you have to assess how frequently the frame is loaded vs. the content being swapped.
This academic video site has pages that run around 55 -100kb http://www.open-video.org/
The Washington Post homepage is 500kb or NY Times is 300kb.