Well an origin of:
An alien speices gets more technological, and one day, they break the machine/man interface wall, where you can put a chip into your head and control, your microwave, write a text, etc. with just your thoughts. Things go well for awhile, most people on the planet get the interface, or a good chunck of the populace.
Then you either have a government, not necissaraly a "World government" but maybe one of those tin pot dictators that don't like free speech stuff, that turns the chip to a mind control type, where they like the dictator, or vote "the right way" or think the right way..
Or some jackwagon tries to break into the chip via a virus or some other thing to get files, memeorys etc, and he screws up and makes the chip a control chip, in that the chip is now in control, from maybe a central location via wifi or something..
So you have a percentage of the popluace that is now in control via there brain chip, and then they see the other populace as people to be absorbed in to the "collective" and it gets out of control of the hacker/despot/government and it ends up the hole population is "One of Us" and they steadaly progress to space, then conquor.
Or it may be something that the people willingly did it, to hear others thoughts, or to connect to each other, and it went to far.