For decades, sci-fi writers have fallen all over themselves decrying a
future where human beings have gone cybernetics-crazy, modifiying
themselves beyond recognition into half-machine creatures that interface
directly with the overly networked world around them (Warren Ellis' Mek and Charles Stross' Accelerando being but two more recent examples). Personally, I think they way undershot the more terrifying possibilities.
A brain-computer interface has been seen as the Holy Grail of cybernetic design for pretty much forever (if the idea makes it into an almost 25-year-old Clint Eastwood movie, it's pretty much old hat). Now that somebody has gone and built a crude working neuralink, we can start getting into the reality of it.
And that reality is: ubiquitous broadband wireless + working machine-mind interfaces + no constitutional guarantee of privacy = thought police.
Imagine a law enforcement agency getting a warrant to wiretap your thoughts. We may be a century off from that, but it's way more plausible than most people are comfortable thinking about.
Worse, we'll probably ask for the technology, because from certain
programming/design standpoints, it's far simpler to teach a machine how
to interpret explicit neural impulses than it is to teach a machine to
recognize the polyglot mess we call human speech. That, and nobody will
want to have to speak their private commands out loud, sully themselves
with dirty physical interfaces (especially in public), or undergo
surgical implantation of wireless uplinks. The answer will be always-on
wireless thought connections, which means an Internet that can read
your mind at a moment's notice. Your notice, or someone else's.
Something to think (and tremble) about.