Hot Map is just a bunch of scanned in paper maps that you can navigate around. SO SO superior to computer generated maps like Google. See for example Bangkok ; give me a good paper map and I'll beat anybody relying on electronic maps and GPS in a scavenger hunt.
It's funny reading about Julia Child and Craig Claiborne and that era of food in America, when you could become famous just by introducing America to some exotic new dish from foreign lands, like "spaghetti". It used to be so easy to travel and see things that you've never encountered before. It's such a fundamental part of human nature to explore and discover and bring things back, and it's basically entirely gone from our lives, which is a damn shame. These days if you discover something it's just because you are uneducated - you could have easily known about it before your journey if you were a better googler.