Strava has become the common tool for runners that has won, over other options. For me, it's a nice way to log my training mileage, and track my shoe mileage. I like how it shows the map and the elevation profile, and I like to see what runs others are doing. I can even export the GPS and put it into a custom Google map so people can navigate with their smartphone and not get lost.
It's also got a social/competitive aspect where people can leave comments or kudos, and you can compete for best time on a segment, and in contests like "most miles this month". btw, Karel is running second to Pete Kostelnick this month, who is running roads from Alaska to Florida. I had a friend who constantly bugged me about where segments were on my mountain that he wanted to take. Big deal, buddy, you hammered a mile a few seconds faster than Ian Sharman did during a 100K, and he wasn't even the fastest, just the only elite on Strava for that race. Needless to say I stay out of that part of it.
To me, where it falls a little short in the FKT aspect is that I think actual sightings can help. What's to keep 2 guys from splitting time with one watch? Or in the case of a road run, hoping on the back of the RV for a number of miles, like that Young guy apparently did. Selfies with metadata helps, but unless you take one between each crew accessible point, there is still some question. I like the idea that I could see the tracker coming toward me, and I could hop on the trail unannounced and see that it was Karel running with the watch. If you're running in stealth mode, it's a lot harder to prove. Again, not that I suspected any fakery, but it was nice to see for myself.