The phrase "What would Jesus do?" became popular in the United States in the 1890s and again in 1990s as a personal motto for thousands of Christians who used the phrase as a reminder of their belief that Jesus is the example to be followed in daily life, and to act in a manner of which Jesus would approve.
The W.W.J.D. (What Would Jesus Do) application is a reminder to remain on the path that Jesus set for us. It is simple, clean, and it's purpose is clear and straightforward without any distracting graphics or unneeded interfaces.
It simply reminds you, W.W.J.D.