I second your motion. Initially I thought that they found a new material that is sensitive to 2.4GHz electromagnetic waves. This train of thought was inspired by the ability of cameras today to capture infrared light. [The old point remote at camera trick].
The title of the original article is "Invisible WiFi Signals Caught on Camera." I thought "Invisible" was too Ripley's-Believe-It-Or-Not-sounding so I removed it while trying to keep as much of the original title as possible intact. Probably a better title would have been "WiFi Signal Strength Caught on Camera" or the one you proposed, but, whats done is done.
Supposedly at one point decades ago PARC had a wire in the ceiling that rotated and whose rotational speed was dependent on the amount of packets traveling in the internet cable strung above it.
(apocryphal?) (what is the truth of this?) (is it still there?)
I believe Facebook is supposed to have a restroom in which a white noise privacy background is generated from global friending/unfriending activity.
The artist in me wants to smile, but the RF guy inside says, "Hey, they recreated the radio signal coverage map with fewer dimensions and less useful information!" (chuckle...)
I love the possibilities here. I want to see rows traced out! Make something that looks like a Joy Division album cover. Use a bullet-time array of cameras to make a video. Make an augmented reality layer so you can see it as you wander the area.
Its a cool visualization nonetheless, but the title is a little misleading.