Valve updated the Steam Controller software, driven mostly by community feedback, statistics, and direct enhancements from lead users. This update allows users to bind media key inputs to the desktop so that the controller can adjust volume, play, pause, and skip when it is not being used to game. They also added context menus for hotkeys, so they can be accessible from the controller without each action taking up a whole button. It sounds like an analogy for the Q command rose in games like Battlefield, just in your input device drivers (and customizable).
There were two other features that caught my eye. First, controller profiles will soon be sharable for non-Steam games (if you add them to your Steam library). This may or may not be useful for titles from Blizzard or Riot Games. Would sharing profiles really help these games be playable with a controller? Either way, there are certainly some titles that will benefit from this, especially those purchased on GoG. The other addition is “Controller HUD.” Basically, when enabled, it shows the pressed inputs on screen. It sounds like Valve intended this to be a debug mechanism for creating profiles, but it could be very useful for video streamers (especially speedrunners).
Lastly, and this is purely for entertainment value, Valve published a video of their factory. Someone decided that it would be hilarious to stick Aperture Laboratories on various machines. It's pure promotional fluff… but cool fluff.