Code hidden inside the latest developer release of iOS 4.3 reveals  Apple has plans to challenge Facebook and more recent social media sharing systems like Instagram with a new, friend-based, live sharing system.
Inside the most recent release of iOS 4.3's developer test edition is a folder called Media Stream and related directly to this are features in the code called "Photo Streaming ." By peering into the data, industrious hackers have  discovered  they relate to a system that'll let iPhone users (and presumably iPad users, when the camera-equipped iPad 2 arrives) live-share any photos they've taken with their smartphones over the air.
It's essentially a development of a feature that Apple's been using for some time, without too much fuss, inside its Mobile Me Gallery service. In this case you've been able to uplink photos or movies taken on Apple products to a gallery location inside Mobile Me, and share with other users either via a private weblink, or directly into iPhoto through an RSS-update feed.
The new Photo Stream system is an expansion of this. It will make sharing more automatic and transparent (also leveraging more modern tech than the slightly clunky manual system Apple had been using), and while, at first, it is designed to automatically, and wirelessly, share the last 30 days worth of photos taken on an iPhone on the user's iPad or Mac, it's social sharing angle is potentially enormous. Plus it appears like Apple will be attaching API hooks to its new Streaming system, which will let third party developers access it for their own purposes.
The feeling is that Sharing may be tied to a "Find My Friends" feature that was also discovered  in code fragments in an earlier iOS 4.3 release--this system is an enhancement to the existing "Find My iPhone" trick, and will be a little similar to Google Latitude. It also taps directly into the current trend for location-based gaming from services like Foursquare. With the expectation that Apple will turn every iPhone into a wireless hotspot in a future iOS update, the opportunity for all sorts of app-based spontaneous wireless network sharing with friends, and even strangers, is pretty large.
So is Apple genuinely pursuing a push into social media sharing, and location-based gaming and trying to beat Google at its own game, while simultaneously challenging rapid-success stories like photo-sharing system Instagram ? It's beginning to look that way, although we can't tell if Apple will promote these new powers aggressively or maintain them as a kind of background default way of doing things that third party apps can do much more flashily. The one fly in the ointment is an existing iOS app  called, fittingly, Photo Stream that lets you send a "live stream of photos to any iPhone, Blackberry, any other smartphone, or any computer."
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