I saw nothing in there about fitness trackers.<p><a href="https://www.washingtonpost.com/world/a-map-showing-the-users-of-fitness-devices-lets-the-world-see-where-us-soldiers-are-and-what-they-are-doing/2018/01/28/86915662-0441-11e8-aa61-f3391373867e_story.html?utm_term=.dee798749a7d" rel="nofollow">https://www.washingtonpost.com/world/a-map-showing-the-users...</a> is the recent WaPo article titled "U.S. soldiers are revealing sensitive and dangerous information by jogging".<p>> The Global Heat Map was posted online in November 2017, but the information it contains was publicized Saturday only after a 20-year-old Australian student stumbled across it. Nathan Ruser, who is studying international security and the Middle East, found out about the map from a mapping blog and was inspired to look more closely, he said, after a throwaway comment by his father, who observed that the map offered a snapshot of “where rich white people are” in the world.<p>This seems to have nothing really to do with Marcus Ranum's blog post that the OP linked to.