Interactive notifications allows you to respond to notifications without leaving the app.
One of the features many iOS users were waiting for has finally made its appearance in the iOS 8. Till now if you receive any notification the only way to interact with it is to tap on it, which will launch the desired app. But now with iOS 8 you can actually respond to the notification from anywhere without leaving the app you are already working on.
The Interactive Notifications also work on lock screen. This feature is not just limited to Messages app but you can also like the Facebook post or comment or it or handle your calendar events.
Another new feature added to iOS 8 is the frequent contacts, which appear in Multitasking View. When you double tap the Home Button you will now not only see the apps running but also the most frequently used contacts from where you can either call them or message them.