Such as www.braintreepayments.com. I see this type of design so frequently nowadays. It's so common that it looks like a template, yet all kinds of companies that you wouldn't think would be using web design templates are using it. Is it becoming some sort of a standard?
It's because the page content is typically on a light background. The dark footer clearly visually delineates the 'page content' from the 'site footer' area using contrast.
It clearly indicates the law of closure or the way a site gets binded up well with a darker patch at the bottom. This is really against a contrasting color that the black works. The footer is a great area also to unearth some of the information/link that we do not find somewhere else. So keeping a distinct color such as black, always a design decision but sometimes this has become a pattern where designers and managers automatically put that band, since its a wise decision and not a show-stopper.
From an aesthetic perspective, the dark mega footer "closes" the dark header. This way the content on the light background is sandwiched between two dark elements. This reuses the design language introduced in the header to draw attention again to the footer.
I think there is a connection with other questions on mega-footers, which have become popular of last, and there are differences in the way they need to be presented. Mini-footers were largely there to contain the stuff that no-one normally read, so were often done in relatively low contrast - they were there, but there was no need to draw any attention to a few pieces of writing at the bottom of the page.
The Mega-footer approach, however, requires the details held here to be clearly visible. As the normal styling is to have the page background light, and the writing dark, it makes a lot of sense to provide a contrast to this and make the mega-footer background dark, and the writing light.
So I think it is less of a "template" as such, and more of a style that has been shown to work, and so one that most designers will follow.
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