It's actually a dashboard navigation pattern posing as a standard horizontal navigation menu. On both sites it's the 2nd-level navigation and it disappears once you drill down into one of the items - which is the dashboard navigation model. But in terms of visual design it's a regular horizontal menu. I think that in both cases it's not a great solution because it draws the attention away from the real top-level navigation, and you don't even notice it at first. Then again, this may have been the goal.
It's most frequently found on mobile, not so often on the web. It's appropriate for cases when you don't expect your user to jump directly between sections and you're ok with forcing them to return to the home page in order to drill down to a different section.
Often a homepage will employ some sort of dashboard navigation mechanism, but then will also provide the menu on the internal pages in some minimized form (e.g. a dropdown or a horizontal/vertical bar), to let the users go directly from section to section.
They are just horizontal menus. The SitePoints one could be considered a list of tags more than generic site navigation.