We're not a big fan of iphoneography in general - too limited in capability, and images really fall apart when subjected to any kind of magnification or enlargement, making them suitable for web publication only. But when IOS 7 made its debut, we had to give it a try.
Some of the builti-in filters seem to have interesting possibilities. The monochrome filter, for example, seems to render images with a 19th century postcard appeal. And the cross-processing filter produces something akin to a cyanotype. Wish there was a way to influence the degree to which a filter is applied...maybe in a future release?