Sect and cults are sociological terms that describe groups that have broken away from the main religious group. Sects and cults, therefore, are no longer within that group. In other words, the main group wishes to distance themselves from the sect or cult. They see incompatibility. In essence they see something new. Sects and cults are fully aware of this fact and they, too, seem themselves as different.
Since, there is this distancing, they are called new religious movements. Sometimes, cults and sects try to reform the main religion and they fail to do so. So, they leave. Other times, there is a charismatic leader who rouses people to follow him or her and a group leaves. In all, the basic point is that something new is created. So, sociologists call them sects and cults.
Cult examples throughout history where many first, the gnostics whom had traditions similar to Islam actually where considered as cults for over 300 years they soon diminished, yet some christians should thank the gnostic movement because they played a huge role in the Reformation even of america some of the founding fathers where gnostics here is a excerpt from Benjamin Frankilin:
Hidden as unseen bless this nation and give reason & knowledge to those that do not have it. Kindly we must have tolerance of ones beliefs as well as tolerance of ones religion without this we as humans can not get along, but only war will consume us all!
Benjamin Franklin 1778
He also believed in aliens........but thats another story
Well I believe in what is orthadox which what religion is morally right. Their is only three types of christianity that have survived as never changing thats Eastern orthodoc, Roman catholiscism, and most represented Coptic christianity which is the oldest type. Actually a cult is whatever you want it to be like if someone combines islam,judaism, & christianity together that would be a cult to some eyes, but to others it could be a way for peace. A sect happened all throughout history from Messianic Jews or even pagans who worshipped Mythras the superhuman god. Actually the bible and the koran does not detail how to truly worship god, it's basically only by prayer and thats all you need. You follow the path of murder yet the holy books do not state kill at all costs it says mainly to defend yourself and the religions of the world are to defend yourselves from evil. Some religions go way to far and sin even though morally it is wrong. The new religious movement are mainly "spiritual awakenings." The world now is becoming more spiritual going with prophecy, yet their are those who go against religion which america & some third world countries have built upon. Religion is in fact harmless it is our defending of the faith that matters.