AirPlay Mirroring – You define AirPlay Mirroring settings in the Display Preference Pane. You get the ability to choose if the feature is on or off, and if you want the mirroring icon in the menu bar.
Notes – The main Notes screen looks like a pad of yellow ruled paper. Structured like Messages, the left side of the Notes screen contains individual documents. The right side contains the actual note on the ruled, yellow “paper.”
Notes – After a note is created, its title is placed on the top of the yellow ruled paper and recorded on the left side of the window as well. New Notes are added by clicking the plus button on the lower left corner. Notes can be stored on your Mac or in iCloud, depending on how you have the app configured
Twitter Integration – Apple is giving you the ability to tweet to your heart’s content from apps that directly support it. Safari is a great example. Click the little birdy, and you’ll instantly get a What’s Happening screen.