For the first time ever, Samsung releases two Notes at the same event, and for the first time EVER Samsung releases an Official smartphone product with a Flexible AMOLED Display, Introducing the Samsung Galaxy Note 4 Edge. The name isn't random, the right edge of the screen folds to cover the side of the device and enable unique interactions, Samsung finally used its YOUM Flexible panels on a flagship device.
The Galaxy Note 4 Edge is based on the Galaxy Note 4 internally, but it's the screen that makes all the difference. The folded side adds an extra 160 pixels so the resolution grows to 1,600 x 2,560 (the highest Res. on a Smartphone device ever) but it also makes the Galaxy Note Edge a bit wider than its straight-screened sibling. Samsung has added enough smarts to the curved side that accidental touches to it are not a problem.
With the phone locked, the curved side can display the Quick Glance info (time and notifications). When you wake the screen, the side displays notifications for various features, including timer and flashlight shortcuts and even a ruler (which works surprisingly well on the curved side).
With the phone finally unlocked, the number of options grows threefold. You can keep shortcuts on the side for easy access or use the curved side for at-a-glance info. Or you can use it to enhance multitasking by switching between several screens (e.g. virtual desktops). Event switching between the pages of the homescreen or the app drawer is also handled by the curved side.
Individual apps can put the curved side to use too, usually to keep the main screen free from clutter. Both the camera and the video player put their controls on the side so the screen is left to the viewfinder/video. Samsung will release an API to enable third-party devs to utilize the potential of the curved side as well.
As you can imagine, the Samsung Galaxy 4 Note Edge experience revolves mostly around the curved side of the screen. Beyond that it's a Galaxy Note 4 with Snapdragon 805 or Exynos 5433 chipset, Android 4.4, 16MP OIS camera and S Pen stylus. The Note Edge has a slightly smaller battery (3,000mAh vs. 3,220mAh) and the USB port moves back to version 2.0.