I have been using analytics software for a while, and I’ve been asking myself how can such software copy a webpage completely to then place it in an iframe and overlay it with images and info.
An example:

A major problem I encountered is copying the webpage.
In particular, copying the webpage the user is currently viewing! (account panel, form journeys, etc…)
I guess this could be achieved by sending the html with the usability data, but I see this as a major performance problem…
Any comments on the subject? This would be very interesting! =)
Further findings:
- I discovered that sending the HTML over GET, could be made mode efficient by using client-side compression. Although I’m still not 100% convinced by this!
I think they don’t actually copy the whole page for your visitors, all of what they need, is to track the mouse location (x and y coordinates) and a url of the current page being shown,
then they will make use of these information to show you all kind of information (where the user was looking, what have been clicked, … etc).