That's not a bad idea at all. The following is the main issue: We don't own the GPS companies (Garmin, Tomtom etc.), nor is any of there software open source. The trick would be to find a way to pitch it to them, such that they need you and won't just steal it and cut you out of the picture entirely.' The way that Garmin currently works is that it will in fact list all points of interest under a category with regard to your proximity. They also have an option to purchase Zaggat ratings for all restaurants in the US etc. It wouldn't be too far fetched for them to also implement a system where certain companies pay to have their logos pop up on the map as you pass them. The questions is once again, where would you fit into the picture? What service could you provide to Garmin/other that they cannot either do themselves or do not have the capital set aside to implement?