There are many AR apps which are targeted at sport and leisure activities, but these activities tend to take place in areas with no data connection (e.g. hiking, running, kayaking). There are many potential uses for Layar in these scenarios, but I can't find any mention of the ability to store layers for offline use. This would let people view layer details without having to query the server. I appreciate that this would shift the burden for calculating which POIs are in range from the web server to the iPhone, but this could be used only when there's no data connection, and maybe refresh less often, for example.