The History of WWJD
Wikipedia encyclopedia states this about the common abbreviation WWJD: The phrase "What would Jesus do?" (often abbreviated to WWJD) 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 initialism WWJD is sometimes used by Christians to mean "Walk with Jesus Daily".
History of the term: Though variations of this phrase have been used by Christians for centuries as a form of imitatio dei, the imitation of God, it gained much greater currency following Charles Sheldon's 1896 book, In His Steps. Sheldon's novel grew out of a series of sermons he delivered in his Congregationalist church in Topeka, Kansas. Unlike the previous nuances mentioned above, Sheldon's theology was shaped by a commitment to Christian socialism. The ethos of Sheldon's approach to the Christian life was expressed in this phrase "What Would Jesus Do", with Jesus being a moral example rather than a Saviour figure.
Sheldon's ideas coalesced with those that formed into the Social Gospel espoused by Walter Rauschenbusch. Indeed Rauschenbusch acknowledged that his Social Gospel owed its inspiration directly to Sheldon's novel, and Sheldon himself identified his own theology with the Social Gospel.
In this popular novel (it had been translated into 21 languages by 1935), Rev. Henry Maxwell encounters a homeless man who challenges him to take seriously the imitation of Christ. The homeless man has difficulty understanding why, in his view, so many Christians ignore the poor: "I heard some people singing at a church prayer meeting the other night, 'All for Jesus, all for Jesus, All my being's ransomed powers, All my thoughts, and all my doings, All my days, and all my hours.' "and I kept wondering as I sat on the steps outside just what they meant by it. It seems to me there's an awful lot of trouble in the world that somehow wouldn't exist if all the people who sing such songs went and lived them out. I suppose I don't understand. But what would Jesus do? Is that what you mean by following His steps? It seems to me sometimes as if the people in the big churches had good clothes and nice houses to live in, and money to spend for luxuries, and could go away on summer vacations and all that, while the people outside the churches, thousands of them, I mean, die in tenements, and walk the streets for jobs, and never have a piano or a picture in the house, and grow up in misery and drunkenness and sin."
This leads to many of the novel's characters asking, "What would Jesus do?" when faced with decisions of some importance. This has the effect of making the characters embrace more seriously Christianity and to focus on what they see as its core--the life of Christ. In the novel, men and women respond in different ways; in contrast to the men who vow never to act without asking what Jesus would do, the women's task is self sacrificial. For example a singer gives up her voice, both in the sense of yielding her singing to the cause and in the sense of silencing the individual expression of her personality.
In 2005, Garry Wills wrote "What Jesus Meant," in which he examined "What Would Jesus Really Do" (also a book review in Esquire Magazine). The expression has become a snowclone and inspired countless variations, usually for humorous effect.