When a magazine coloured its black dots

Why would a brand want to colour all the black dots in an entire edition of a magazine?

Eir Telecom had a reason. The coloured dots suggest that eir can help eliminate “black spots” in your home or office where your mobile signal is weak. No More Black Spots went the headline of the ad that accompanied this stunt in the October 6th issue of the Daily Mail magazine.

It was not an easy task. Agency Rothco had a tough time convincing newspapers to accept this stunt. Finally, it was the Daily Mail which accepted the creative and actually loved the idea. What Rothco wanted to go was create a really simple analogy for what WiFi calling actually does - it eliminates black spots.

What could be a more striking way to convey the message?

Source : http://www.adweek.com/creativity/this-crazy-ad-replaced-every-black-dot-in-an-entire-magazine-with-a-colored-dot/