Why write about cults?

There are so many non-Christian cults out there that look good on the surface and say most of the right things but once you start to dig a little deeper you find out how dangerous these groups really are. I have been doing a lot of research into most of these groups like the Mormons, Jehovah's Witnesses, and Roman Catholicism. These names look very familiar to most of you but what do you know about Christadelphianism, Christian Science, Church of Christ (ICOC), Open Theism, Shepard's Chapel, The false apostle Eric vonAnderseck, Ronald Weinland, etc. Not much I am willing to bet.
This would not be a scare tactic presentation. It would be fact based using these groups own writings and comparing it to what is written in the Bible. The world we are living in is a dangerous one and the secular community is constantly trying to water down the scriptures and Christianity as a whole. The world is moving more and more to a one world faith and it is trying desperately to drag us along with it. And what is worse is that the average Christian does not know enough about their own faith and doctrine to escape it.
I will be using many different sources for these studies but will list them all so that all credit goes where it is supposed to. A lot of these places have done extensive research and I do not want to take credit for other peoples work.