When I read an article at Salon.com I notice that the "overflow content" (where I need to scroll down) is loaded on demand. I can't imagine this being a useful bandwidth savings technique, so the only reason it might exist is to collect information about the end user.

  • Is this feature more focused on analyzing user behavior than saving bandwidth?

  • What is this technique called?

  • What do providers do with this information?


4 Answers 4


Is this feature more focused on analyzing user behavior than saving bandwidth

I think the original goal of it was to increase responsiveness by reducing the amount of time until the browser is fully able to render the page.

What is this technique called?

Effective leveraging of AJAX

What do providers do with this information?

It probably provides a more accurate view of dwell time and reader behavior as one of those side-effects that became a driving force.


The reason behind this feature is to load a page more quickly. It really is no different from the idea of paginating a grid or forum. It just adds the convenience of automatically loading additional data for the user so that they don't have to hit a next button. It's simply dynamic loading through AJAX. The information is similar to the information provided by the previous technique of having a next button to get more content.


This is very similar to the recommendation playlist in Youtube on the right panel of the page when your watching a video. Its an expensive process to go look for all related resources when the user may not be interested in looking at them!

In this case - I would say its an optimization where they do not want more calls to be made from the client when all the user does is read the first few lines of the article and moves away.


For most cases, the feature is there because it is fashionable. The customer saw it on a site and loved it, the site developer just learned how to do it, so they both insist on doing it, and rejoice.

In some cases, it is a really useful tool for saving bandwidth. An example is Image search on Bing: images do use non-negligible bandwidth. Images will be downloaded "on demand" and the page virtual length is effectively infinite (at least, as infinite as the Internet supply of pictures of cute kitten).

The technique is sometimes dubbed "infinite scrolling". Whether it is a good idea is debatable and debated.

What the content providers do of the information is unknown. Methinks they make some statistics, if only to optimize the amount of background preloading for the infinite scrolling feature. In the case of an image search, the terms used in the search box are much more damning to you than your scrolling behaviour anyway.

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