iOS 5, Apple’s new mobile operating system, was shown off at WWDC. As expected, the new version includes a brand-new notifications system, and system-wide social integration. Here’s everything you need to know:

Features

Notifications Center: all current iOS users know that the current notifications system was showing its age. Apple has turned that around by building a new system, which unobtrusively displays all notifications at the top of the screen, even during games, and on the Lock Screen. By sliding them down, users will be able to visualize all unread notifications, or dismiss them completely by hitting an "X" button next to them. Very straight-forward. Notification can include missed calls, voice mail messages (which can be played right from the Notifications Center and even notifications from other Apps.
This system is very similar to MobileNotifier, which isn’t surprising, since the company has recently hired its main developer.



Reminders: this feature, as the name implies, allows users to set different reminders for different times of the day, and different places. Thanks to the geolocation support present in devices, users can now configure Reminders to pop up a notification at a certain time and at a certain place, and even sync across devices using iCal. It’s really to-do lists on steroids!


Enhanced Safari: The iOS browser now looks a lot more like its desktop counterpart, with a few extra features of its own. Tabbed browsing now looks identical to the way it looks on the Windows and Mac versions, with tabs displayed across the top, at least on the iPad. The new Safari also brings the Reader feature, displaying a website’s content in an easy text only view, but unlike what happened before, users are now able to bookmark content onto a "Reading List" for later or send it to friends.


Twitter Integration: as rumored, the new iOS 5 includes deeper system-wide integration with Twitter. While there’s no support for other social networks, this feature is integrated with many apps, including the Camera App, allowing you to quickly tweet out what you’re working on. You can log into Twitter from System Preferences. It’s a single log in.


New Mail client: similarly to what happened in Lion, the iOS mail client is also receiving an upgrade. The App now supports draggable addresses, as well as the ability to flag messages and search them and dictionary lookup, by tapping on a word and selecting "Define".

iMessage: it’s like iChat for iOS users. It lets you send text messages, photos, videos and even have group conversations, similarly to any other messaging client. This application is also a great new example of how Notifications Center, since this App interacts beautifully with it. With this out the gate, I one is left to wonder what will happen to iChat.

Independence from computers: Previous versions of iOS required users to connect them to a computer in order to set them up, update them or sync them. iOS 5 will put an end to all that, by allowing users to update the device over-the-air. There’s also a new set-up wizard for new devices, allowing them to be configured for the first time without the need for a desktop computer. Can those who hate iTunes finally proclaim victory?

Tens of small additions: iOS 5 includes a number of small improvements, such as direct game downloads in the Game Center, a new optional keyboard, enhancements to the Music App on the iPad and an enhanced Camera app.


Here is an official video of iOS 5 features in action: