I heard 10.10 will have windicators, what are they? How will they look?
This article explains it best with mockups, etc. The jist of it is though. Much like the new Indicator Applet, Windicators will actually be an Indicator that sits on the window likely occupying whatever space the window controls (Min, Max, Close) aren't. They can display status messages like whether the current screen isn't save, the application is busy, or a variety of other indicators. This should take the guess work out of some applications and help streamline others - the intent upon which is to make the UI more accessible to the user.