I really wanted to avoid using this word on my blog because of people's biases around it. However in the effort of dismissing stereotypes, it cannot be ignored, especially since it has become a topic of interest to non-Muslims. Have a listen to this interview with a former (more or less) associate of the movement. For a non-Muslim, or very lay, secular, or vastly westernized Muslim (and I seek refuge in ALLAH from being all three), this is quite accurate, but not appropriate for a Muslim who knows the religion well enough to make a proper distinction.
For the Muslims, a better explanation is as below, and I personally endorse this understanding as a Muslim: