A FON map is a locator for FON spots, which are distribution points for a global wireless connectivity platform called FON. With FON, users share bits of a single Wi-Fi endpoint connection to enable more flexibility for hooking up laptops and devices to wireless networks.
Techopedia explains FON Map
FON maps show where available FON spots are located all around the world. These maps typically shows subsets of more than 4 million FON spots where those with FON access can use local Wi-Fi signals.
FON maps often feature both map and satellite views, and are zoomable maps that can zero in on a given location. These maps allow FON enthusiasts, who are often called "Foneros," to see where available FON spots are located relative to each other and to their own location.