Really like the concept - lovely visualisation. My comments:

- The URL length limit is way too low! If I want to test a specific asset that's delivered by CDN there is no way to do that

- The colours seem inverted (I'd expect green for fast, red for slow) but this may be a cultural thing

- I'd dampen down the grey a bit, it looks like it's a measurement but really I think that's just places where no test was performed?

- Presumably you know where you can get measurements from so perhaps the initial map should be dual toned to reflect that