It's an app that shows you the direction to the nearest radio tower. You basically turn it on and it points to the nearest one, with a compass so you know the direction to point your antenna in. I have only done it in Sweden so far, so feel free to develop a similar app in your country ;)

Do you know much about how/why people find your app? When playing with a TV antenna, I wouldn't think to search for an app that could help. Seems like you are getting plenty of people finding it, though.