Windows Phone 8.1
Windows 8.1 (big update)
New Nokia models
Surface 3
I would also not be surprised to see an announcement of an acquisition in the dev space, Xamarin comes to mind but I dont think that will happen (yet).
TS has been in release candidate for some time now, and it feels ready for stable 1.0. I suspect we'll see that announced today.
They're all the same OS (and the same OS release) with names tacked on to differentiate between minor releases.
MS probably feels they are significant enough to keep calling it "Windows 8.1" as the product name. At the same time, Update 1 might be insignificant enough that it's not worth calling it "Windows 8.2".
Xamarin's twitter feed has been kind of quiet today.
Am I wrong?
So, for example, maybe Azure upgrades/SDK changes. Visual Studio updates, .net framework, etc... All the other sessions are deep dives into the tech and how to use it
Windows is a behemoth that needs to support a ton of different hardware configurations, and it can't come out until it works very well on almost all of them. That means a year of development is a very short amount of time for Windows, and they can't add too much to it. Look at Windows 7 vs Vista. It took 3 years just to improve its performance a bit.