Bookmarked:
rauno.me 
Nothing beats a thorough examination of a niche topic. Such I found in this article by Rauno Freiberg, which dissects the metaphors of interaction design in search for the small and often implicitly applied details they consist of:
Design can feel like there’s no science to it — only feel and intuition. Even researchers have trouble grounding interaction design practices in science, inherently treating them as a mysterious black box. While from my own experience that’s partly true, I have been trying to deconstruct and dig out the why behind great displays of interaction design.
[…]
This essay is not a tutorial nor a collection of guidelines. But rather an observation on the invisible details of a few interactions that I use often but rarely think about. Besides recreating interfaces, I found this exercise in reflection to be another great way to build a stronger design intuition and vocabulary.
…and the brilliantly simplistic “operating system” design of the website itself is just as fascinating!