What are the principles, use cases, and/or motivational factors behind placing content that pertains to the main body of the site, to instead exist below the footer?
I want to better understand the reasoning behind this design choice.
TL;DR
A few moments ago I visited the Apple site to view their catalog. After configuring a Macbook Pro (MBP), and scrolling to the bottom of the page, I was confused as to why I didn't see a price for the machine I had configured in the main area, so I scrolled up, thinking I missed it, scrolled back down, didn't see it.
What I realized is that I had falling into a trap. For years, I have been trained to assume that all main content is in the body of the page, below the header, above the footer. So my mind was actively ignoring everything below the start of the gray footer, even though I was actively looking for the information that was being presented to me below the footer of the page.
Based on my experience with developing web applications, understanding user's expectations, and basic UX principles, my question is, What are the principles, use cases, and/or motivational factors behind placing content that pertains to the main body of the site, to instead exist below the footer? I want to better understand the reasoning behind this design choice.
It is important to note that the footer you see containing the price information for my computer configuration is part of a fixed footer that did appear at the bottom of the page, above the footer, until I had scrolled all the way down to the bottom of the page, where it instead then was below the footer, so I had ignored it.
Screenshots: (notice how the pricing information bar is positioned at various scroll positions of the page)
Firefox
Scrolled to top:
Scrolled to middle:
Scrolled to bottom:
Chrome
Scrolled to top:
Scrolled to middle:
Scrolled to bottom: