The addition of tabbed browsing and wireless syncing of contacts and calendar aren't the only features that Apple's playing catch-up on, as compared with its mobile competition.
Apple has, finally, introduced the ability to use the volume up button as a camera shutter button. Many Android and Windows Phone 7 phones have had physical shutter buttons for a while now. (Other additions to the camera: The inclusion of gridlines for framing images, built-in image enhancement software, and a shortcut to the camera app on the lock screen.)
GameCenter, launched nine months ago, has 50 million users now; Apple pointedly noted that Xbox Live has 30 million users, amassed over the past eight years. Without saying so directly, Apple squarely pitted its GameCenter platform for social gaming against Microsoft's Xbox Live and Windows 8 integration. In iOS 5, GameCenter adds such features as achievement points, the ability to see friends of friends, friend discovery, game discovery through recommendations, and turn-based gaming.
Meanwhile, with iMessage, iOS 5 takes on RIM's aging BlackBerry Messenger platform. The new iMessage platform works to send messages to any iOS device, regardless of whether it has SMS support. With the new platform, you'll be able to send messages to users of Wi-Fi only iPads or iPod Touches, which couldn't easily receive standard text messages. iMessage will tell you whether someone has received or read your message and give you an indication that someone is typing a note. It also provides encryption to protect your communications.
While iMessage puts the squeeze on instant messaging apps, third-party Twitter developers saw iOS encroach on their turf, too.
In another sign that Twitter has become synonymous with daily mobile life, Apple has integrated Twitter directly into its operating system. With iOS 5, you won't need to re-log in every time you want to tweet, and sending tweets-including Web links, photos, YouTube videos, businesses and locations from Maps, and contacts--becomes as simple as a menu tap option, as seamlessly as if Twitter were a native app.
A couple of the highlighted new features fell flat. One example: The addition of a new reminders app. While what Apple showed appeared slick enough, it was unclear to me what advantages its app will have over the scores of existing to-do list apps. One plus, though: Your reminders sync with Microsoft Outlook via Exchange, and with iCal.