It's not a doctrine or a school of interpretation; it has no position on the Class A Comment or the identity of the child of the Prophet, nor does it have a standard program of study. In fact, it's not really a form of Thelema, but rather a particular social form adopted by some Thelemites. What sets it apart from the more typical social forms of Thelema is that the determining level for all questions of principle and practice is the congregation, as it defines itself, and not some board, council, synod, or patriarch which directs the affairs of multiple congregations, as they define them.
It is perfectly possible for independent Thelemic congregations to work together and even to join in larger organizations, as long as each congregation retains its right to decide the issues of its own principles and practice. Because of that absolute right to define themselves, there can be Congregational Thelemic groups of widely varying natures, from local personality cults to anarchist collectives to democratic neighborhood churches, and even more diverse (and more ephemeral) online congregations.