The Borg manifest as cybernetically-enhanced humanoid drones of multiple species, organized as an interconnected collective, the decisions of which are made by a hive mind, linked by subspace radio frequencies. The Borg inhabit a vast region of space in the Delta Quadrant of the galaxy, possessing millions of vessels. They operate solely toward the fulfilling of one purpose: to "add the biological and technological distinctiveness of other species to [their] own" in pursuit of "perfection". The concept of perfection is the unifying idea at the core of the Borg. The pursuit of an unemotional, mechanical perfection is the Borg's only motivation. This is achieved through forced assimilation, a process which takes individuals and technology, enhancing and controlling them.from Wikipedia's "Borg (Star Trek)" entry
In the text commentary to the Collector's Edition of Star Trek: First Contact, Michael Okuda revealed that Star Trek: The Next Generation writers began to develop the idea of the Borg as early as the first season episode, "Conspiracy", which introduced a coercive, symbiotic life form that took over key Federation personnel. It was thwarted by the Enterprise crew and presumably never heard of again (the 'alien conspiracy' plotline itself was scrapped when it became clear that the concept was too grim for Star Trek's target audience). Plans to feature the Borg as an increasingly menacing threat were subsequently scrapped in favor of a more subtle introduction....
As a result of my periodic encounters with organized Satanism in the form of "flash mobs" which are clearly organized to demonstrate its omniscience and omnipotence, I've come to think of it as "the Borg." (Note that "The Borg" just happens to convert to 33 42, i.e. 6 6, and that "Delta Quadrant," their supposed region of space, just happens to convert to 42 96, i.e. 6 66.) I can't be certain of the mechanism used to coordinate these activities, because only those involved would be privy to such information, but sometimes it seems to me like they're spiritually controlled like puppets, because of how quickly they adapt to changing situations, and how inhumanly relentless they are, as if they have no greater purpose than to act as appendages of a "hive mind."