The term "cult" is widely used in our culture today. The problem is that not everybody means the same thing when they use the word. In popular culture, the term cult brings up the image of a small religous group with a charismatic leader that "brainwashes" his followers into living an aberrant lifestyle, often involving weird sexual practices and resorting to physical violence. Usually people think of the Peoples' Temple, the Branch Davidians, and Heaven's Gate.
In addition to this popular definition you also have theological and sociological definitions of a "cult." In some religious circles, the term "cult" is used of groups that have unorthodox theology. For example, in the Evangelical Christian tradition, the organization of the Jehovah's Witnesses is understood as a cult since it claims to have sole access to God and because it claims to follow the Bible, yet denies orthodox Christian beliefs.
Sociologists and scholars of new religious movements tend to reject the term "cult" altogether because of its pejorative connotations. Instead, they use the term "New Religious Movements." However, the term still may be useful in the cult-sect-church paradigm. In this framework, a "cult" is a minority religious group which is in high tension with society at large. A "sect" is a group which experiences less tension and is usually an offshoot of a "church." A "church" then is a religious group which is fully accepted by society. Under this definition, for example, the Church of Jesus Christ of Latter-Day Saints was a "cult" in the nineteenth century but today is more of a "church" in American society.
Do you think using the term "cult" is still useful? If so, how would you define it?