Tonchidot unveiled Sekai Camera for iPhone last year, a social tagging application that uses the iPhone's camera to view the world with tags overlaid over the camera's image so that you can see how others have tagged your environment. It was a big hit. But it was only for the iPhone, and the iPhone doesn't have a way to detect where the camera's pointing, so the tags can't be associated with a specific orientation. You go to the tagged spot, then flick your finger to hunt through the tags associated with that spot.
Soon afterwards, T-Mobile's G1 was unveiled, and one of the first applications we could download was Wikitude, a sightseeing application that grabs your location (from GPS) and orientation (from the compass), then overlays the camera image with information about points of interest. For instance, if you're in my front lawn and you point your G1 south-southwest, the screen overlays the live image with points indicating the University of Texas and the Elisabet Ney Museum - and tells you how far away they are. Great for sightseeing and orienting oneself, but too large a scale for doing what Sekai Camera is trying to do. But notice that the orientation problem is solved due to the G1's internal camera.
This week MobileCrunch reports that Sekai Camera is releasing a version for Android - and it takes advantage of the internal compass. That's great. But - if the majority of tagging is done through the iPhone, I don't think that those tags will be captured with an orientation.