Notification Center, which was introduced in iOS 5 and expanded in iOS 7 with several tabbed views (Today, All, and Missed), will now be greatly enhanced in iOS 8, with new customization features including the ability to add third-party widgets to the Today view. In the current beta, the default in the Today view is Today, Traffic Conditions, Calendar, Reminders, Stocks, and Tomorrow Summary. A new Edit button lets you somewhat rearrange this list and also hide items. Developers of apps can now also develop widgets associated with their apps that you can choose to display on your Today screen. You'll be able to add widgets such as weather, sports scores, and current eBay auctions.
In addition, iOS 8 lets you respond to many different kinds of notifications from the lock screen or from within apps, without having to go to the related app. This was a much-requested feature for Messages. Now it's not only possible to respond to text messages without going to the app, you can also accept or decline calendar invitations, mark an email as read or delete it, and mark a reminder as complete. In addition, third-party developers will now also be able to include interactive notifications in their apps, such that this feature won't just be available on Apple's apps.
Interactive notifications are a real convenience, letting you reply quickly and then get back to whatever you were doing.