Communication technology tends to develop in a particular direction: more people communicating across larger distances using less effort to do so. Taken to its logical extreme, perfect communication would be anyone being able to talk to anyone, anywhere, using no effort at all.
The closest concept we have to this form of communication is something called the hive mind. Everyone would be connected to everyone telepathically, and we could all share our thoughts, memories, and even dreams with one another. Such a system of communication would not only have far-reaching consequences, it would also be hugely controversial.
We (Almost) Have the Technology
Many have theorized about the hive mind, speculating about everything from what we would need to bring it to fruition to what it would do to society.
Some initiatives, like Princeton's Global Consciousness Project, assert that we already have a hive mind; it's just a matter of detecting it. Certain religious groups also espouse the concept of oneness, claiming we are all already connected on a non-physical level. Rather than figuring out how to tap into some inherent ability we already have, however, the most popular theory on how we'll get a hive mind is through technological innovation.
Some brainwave interpreting technology is allowing us to interact with machines through thought. Braingate's wireless brain implant is currently designed to allow severely disable people to control things like wheelchairs and virtual keyboards using their thoughts, but the technology could serve as a direct conduit to other brains one day. We're already making strides on that front as well. In 2014, a team of researchers successful conveyed the thoughts of someone from Spain to a person in France using an electroencephalography (EEG) to read their brainwaves and a computer to transport the information.
For Better or Worse
Few doubt that the technological tools we'd need for a global hive mind are on the way. The bigger question is what we would do once we had the technology.
Obviously, being able to effortlessly share our dreams, emotions, and thoughts with one another would have many benefits. We could create our own virtual worlds and interact with others only in those worlds. Formal education would become a days- or weeks-long process as we would have the ability to download knowledge directly into our brains, and the spread of ideas or viral thoughts would be nearly instantaneous.
It would feel like a much smaller world and how we would interact with others within that world would be fundamentally changed. Unfortunately, that change wouldn't necessarily be for the better. Imagine a hacker controlling "thought databases" or a totalitarian regime going all "1984" on the whole of society. While many claim that privacy is already a lost concept, it would truly become a thing of the past if anyone could hack into your thoughts.
Another, more far-out theory is that we would coalesce into a single entity, like the Tyranid Hivemind or the Zerg Overmind situation in the video above. Through our own volition, or as a natural evolution of technology, we would "upload" ourselves into a singular consciousness. Maybe that would actually be the Singularity many have predicted.
Despite all these technological connections, at its most basic level, the concept of a hive mind is something found in nature, a means by which the many come together to create something better than the sum of its parts. Studies have already shown that we are better at predicting pretty much everything when we think as a group. Imagine the problems we could solve if everyone in the world could collaborate on solutions just by putting our minds together.