When I travel, sometimes I find an area of a city that I would like to explore on a future trip. So, my idea is to have a tool to highlight part of a map and then use it like a pin. That means to make it a favourite and add information to it. It would also be useful when searching to only search within the selected area. Generally, the area could be a circle or other shape. It would not need to be so specific as, for example, a route.
Being able to import KMLs–it’s so easy to map areas in Google Earth, and easier than it used to be to use Google Maps for areas–would serve multiple purposes. But perhaps KML capabilities are copyright/patent restricted?