Ask HN: Iteration 1 of Android App released, ideas for Iteration 2?

I have released the first iteration of an Android app which you can download from https://market.android.com/details?id=com.xqoob.flow It is a marker-based augmented Reality app and at the moment doesn't do much other than work out the distance between two markers. This is very much a novelty feature, my main aim was to get something released, and then iterate multiple times. I have an idea where I want to go with this app, and what gap it fills (a personal itch). However I want to ask you guys two questions - 1) What would be a potential problem the technology in this app could be applied to? 2) Given the functionality that it currently has, what feature would be a good next step to implement? I'll disclose where I want to get to with this app, and what niche it fills, but would like to hear some of your ideas first.