[Here's a little background on the mini-story from earlier today.]
The Totally Radical Borg Collective are a cyborg pseudospecies who roam the known (and probably unknown) parts of the galaxy more or less at will as the whim strikes them. They once threatened to become the most terrifying scourge the modern galaxy has ever seen, but since 2207 they're mostly harmless.
Exactly where, when, and how the Borg originated is unknown, even to them. They're not technically a species unto themselves, but instead reproduce by "assimilating" sapient lifeforms, converting them into members of the Borg community through the installation of various cybernetic implants. This process is not entirely unlike the cybernization process through which the various strains of Cybermen perpetuate themselves, but Borg technology appears to have sprung from an entirely different, possibly alien, base. They seem to favor humanoids; whether this is because the "original" Borg were, like the earliest Cybermen of Mondas, humanoids themselves is unclear, but Borg technology does seem to be optimized for the humanoid body layout.
When they first appeared in known space in 2164, the Borg were a nearly-unstoppable, non-negotiable-with, batshit terrifying force of destruction and identity erasure - the nightmare bogeymen of the late 22nd century. For more than 40 years, they rampaged through a section of the Outer Rim, conquering worlds and assimilating whole populations by force. Those unfortunate enough to fall into their clutches would be mercilessly converted into new Borg themselves, their identities submerged in the relentless anonymizing tide of their wirelessly networked overmind. Able to adapt to most forms of attack or defense, they required the most concerted effort and ingenuity on the part of the WDF and United Galactica Navy to even contain them, much less defeat them. For the better part of four decades, the best anyone could do was confine them to the Hurley sector. The UGN maintained a nervous perimeter watch on what became known as the Borg Exclusion Zone from 2170 to 2206.
In the latter year, Borg forces broke out of the Exclusion Zone, using a combination of newly adapted offensive technologies and overwhelming force to defeat the UGN's Borg Containment Task Force. The rest of the UGN, the Royal Salusian Navy, and the WDF responded with dispatch, but though they were able to slow the Borg advance, even their combined might couldn't halt it altogether. The remorseless cyborgs looked poised to drive into the heart of the civilized galaxy, possibly even strike at Salusia itself.
Enter the Right Honorable David Bowie McMenahan-Chiang, Ambassador Plenipotentiary from the Republic of Bodacious Vee to the United Galactica Assembly. Declaring that the problem with the Borg was that no one had ever been able to explain to them "how uncool their jive [was]," McMenahan-Chiang deliberately allowed himself to be assimilated in an attempt to communicate with the Collective from within. This had been attempted before - many times before - and had never even slightly come close to succeeding. To pretty much everyone's shock, however... this time it did. Within minutes of McMenahan-Chiang's assimilation, the Borg halted their advance. There followed a brief period of confused uncertainty, as the allied forces debated whether this was the moment to launch an annihilating counterstrike.
This action was forestalled when one of the Collective's infamous all-band transmissions reached the allied fleet. Instead of the usual demand for surrender, this was a personal communication from "Dave of Borg" declaring that the Collective had seen the error of its ways and would thenceforth cease harshing the galaxy's mellow. They were, he went on, retiring to the Hurley sector to "have a re-think" now that it had registered on their collective consciousness how unwillingly many of their individual parts had joined the whole.
Shortly thereafter, a flood of dazed, confused, and generally-a-little-bit-off former Borg started pouring out of the Exclusion Zone and back into galactic society, resuming lives they had, in some cases, disappeared from 40 years before. Most ex-Borg retained some or all of their implants, and most harbored little, if any, ill will for their former captors, explaining to the trauma counselors the UG rushed into action that they had, after all, been in on what they called the Great Rethink themselves, and so could not doubt that the Collective's shock, dismay, and regret were genuine. Some ultimately opted to return, finding life on the outside less enticing than the sense of community prevailing within the revised Collective.
It took several decades for the situation to shake out fully, but by 2240 the Borg population had stabilized at around 100,000 willing participants. Having relinquished all the worlds they once conquered, they remaining core of the Collective took to wandering the galaxy in their one remaining starship, dubbed the Ravecube by their de facto leader, Dave of Borg.
Modern Borg society is about what you would expect if you took a hundred thousand Funkotroni and networked their brains in a wireless cybernetic neural-net overconsciousness. Whatever species they may have been before (and just about every humanoid or mostly-humanoid species out there is accounted for in there someplace), they are all now imbued with the zany, happy-go-lucky, don't-worry-be-happy ethos of that laid-back people. Individual members of today's Collective have identities of their own, but they're all still interconnected in a loosely, fluidly confederated overmind, and in moments of crisis (not that there are many of those nowadays) they can revert to what they describe as Emergency Badass Mode. You really, really don't want to tangle with them in this mode. Fortunately, they hardly ever use it.
Most of the time, they roam the galaxy, hosting a perpetual roaming dance party that flits from system to system more or less at will. International agreements, unwritten laws, cultural traditions, and the utter pointlessness of trying to stop them guarantee that the Borg are... well, maybe not welcome... but not totally unwelcome anywhere in civilized space. It's well-understood by this point that they have no political or military agenda whatsoever, don't give a damn about what anybody's government is or is not doing, and won't be staying more than a week or two.
The Borg support themselves by making and selling high-end custom electronics and software, including a few commercial-grade adaptations of their most popular implants, cybernetic inferface equipment of a high order, and some of the absolute raddest hologames you have ever soaked your optic and otic nerves in. Borg gear is sold under a variety of names; if you've ever seen a cyberdeck or gaming interface with the Sandbenders, Hypercube, or R.I.F. brand, you were either looking at a Borg product or one of the inevitable Neo-Taiwanese knockoffs (since it almost goes without saying that the Borg are not too interested in protecting their IP).
One of the keys to the "reinvented" Borg's widespread acceptance is the fact that they no longer assimilate unwilling individuals by force. They do accept new recruits (or "noobs", as they inevitably call them), but they don't seek them; and though their screening process appears lackadaisical to the outside observer, it's actually very strict, especially once the prospective noob is actually online with the Collective. Once that's been done, the others can determine pretty quickly whether the noob in question is genuinely interested and likely to make the grade. Those who aren't are affably but firmly logged back out and told to go home. The ones who pass become full nodes on the network.
It's also possible to leave the Collective, as the great majority of the forcibly assimilated did after the Great Rethink, and individuals still occasionally do. Except in very rare cases, there are no hard feelings when this happens, and those who leave are allowed - invited, even - to keep their implants and stop back by whenever they like. Collective members who joined and left voluntarily are often mistrusted by the members of the original "Borg diaspora", many of whom are still alive today thanks to their cybernetic enhancements. The "liberated", as they call themselves, tend to see the modern "expat" Borg as some sort of galactic infiltration agents, though exactly what today's Collective would need or even think to do with such agents is an open question to virtually everyone else.
As you might imagine, the Ravecube is a very friendly environment for hitchhikers, and at any given time a hundred or more can be found aboard. The Borg welcome sincere hitchhikers as fellow followers of the whim of the Great Magnet. Be warned, however, that they can be quite creative in how they deal with anyone who is up to no good.
This Guide entry was written by MC Supar J 6of14 SECTION 54D ALWAYS THE BEST!!!!OK, doing business as Professor Jason Borg-Warner, Emeritus Professor of Cybernetics and Connected Sociology at the University of Bodacious Vee.