enough interoperability to be able to include Android, iPhone, Blackberry, Palm and computer users all together, no matter which AR client they happen to be using
truly mobile-centric ways to present information and entertainment using your handset's camera and GPS
Point & Find AR application
make money from AR
travel guides and review listings
making them free will hugely increase uptake and where possible spur more user-generated content
money is most likely to come from advertising
who will sell the ads, how much brands will pay, and whether it will annoy users
Many of the companies developing AR apps are small, innovative startups who don't need to turn a profit just yet. They're exploring what's capable with this kind of technology.
when Apple opens the floodgates for iPhone AR apps
prove the business case for users paying for this kind of technology, and/or for advertisers getting involved.