AR apps for iPhone and Android are whizzy, but making money from them will be the challenge.
A wave of new augmented reality (AR) mobile applications has the tech blogosphere buzzing, thanks to overlaying data on handsets' camera feeds.
Examples? Wikitude (pictured) is an AR travel guide that tells you about famous monuments as you point your phone at them. GraffitiGeo serves up ratings and comments on restaurants as you look at them.