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I was searching on Google and I clicked on 1 of the ads related to my search, I noticed on that website that every time I do something like scrolling or selecting text there is a request sent to a file called log.php and the request submits the timestamp, the event type dom.stream, the page url, and some events like the following:


also the request sends the visitor id and the referrer, all of these are sent with everything I do on the website.

This is the first time I see something like this, and I'm wondering if it's for legit purposes or not ? and how does it help the site webmaster ?

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up vote 3 down vote accepted

That kind of information is collected for website usability testing. There is a strong correlation between where the mouse moves and where users read (many users move the mouse near what they are reading).

Knowing where the mouse goes and what users click on gives webmasters a good sense of what users find important and what most draws their attention on the site. With that knowledge, the website can be improved to make the important parts stand out better.

Packages that do this type of logging are typically marketed to webmasters as "visitor recording", "heatmap analysis", or "hotzone mapping". The kinds of questions that this data might typically try to answer are:

  • Why do users not add products to the shopping cart when they visit a page?
  • How many users read to the end of the article?
  • Is this button being used?
  • What doesn't get used/read on this page that can be eliminated?

Here is an example heatmap that might be generated using this data:

heatmap Image licensed Attribution-ShareAlike 2.0 Generic by Beantin webbkommunikation

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Hot Zone mapping. And precisely for the reasons Stephen notes. Expect it on e-commerce sites. It quickly helps us eliminate dead zones and garbage product or rethink how product needs to be presented. If you're on a highly usable website that's functioning better than most, you probably participated in helping upgrade that site by sending that data. – Fiasco Labs Sep 10 '13 at 19:24

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