The first is an adaptable start screen. MS has learned from its faux pas with Windows 8. W9 will adapt itself to whatever you happen to be running it on: If a keyboard and mouse are attached, then W9 (codenamed “Threshold”) will give you the desktop mode. If not, and if you have a touch enabled device, W9 will load the mobile mode.
The second: The Start Menu is coming back. The elimination of the Start Menu was a blunder on MSs part. Perhaps the worst of those tied to W8. So, a brand new Start Menu is coming. The right half is the mobile app mode, the left half being the old desktop type menu, as you can see below:
(picture credit Make Tech Easier)
This will allow you to open the mobile apps while W9 won’t ‘forget’ you’re in the desktop mode.
The third thing is that there’s a rumor that it might be free for users of W8.1 Update2. I wouldn’t bet on it, though…if only because W8 was such a money loser. W8.1 Update2 will happen in August. Also, W9 might happen at year’s end, but more likely in April 2015.