Are we all Homo Sapiens? I'm not so sure

You know we are all humans (at least those of us that use steemit anyway, my dog isn't).
But that is of course not the official, i.e. scientific, name of our species. Biologists call us Homo Sapiens.
You know that, right?
You may also have heard that there were other humans walking on Earth long ago. Notice I wrote "humans" not Homo Sapiens.
That's because those were humans but NOT Homo Sapiens.
The most famous species of them were the Neanderthals.
But there were also other human species, for example Australopithecus, Homo Habilis, Homo Erectus, etc.
And no, contrary to what many think not all those were just earlier stages of our species. We did NOT evolve from the Neanderthals, we are a completely different branch of humans. The Neanderthals did not evolve into Homo Sapiens, they perished. (We did have a common ancestor but that is different).

So, the established theory is that there is now only one species of human ("human" is again, just a generic term) on planet Earth. You, me, your neighbor and everyone you've ever met.
But in the last few years I've begun to suspect -and with very good reason- that there are some profound differences in the population.
And I'm not saying this in a we-are-all-different kind of way.
I'm not even saying it in a I'm-white-and-you-are-black kind of way either.
No. The differences I'm referring to go deep below the skin. In fact, I don't think there are any racial or geographic correlations.

OK, I'll spill the beans:
You've most likely heard the terms Extroversion and Introversion.
Some people are extroverts and some are introverts.
Most people around you are extroverts. Chances are that you are one too.
But there is that one guy who is alone in a corner at a party. And ten minutes later he walks out the door.
There may be many reasons why he does that. It doesn't necessarily make him an introvert.
But introverts are usually like that. They hate being surround by a large number of people. They find most human interactions, especially the haha-what-a-nice-party ones, banal and meaningless.

I'm beginning to suspect that a small proportion of the introverts are "extreme introverts". They truly, genuinely, consider themselves different and not belonging.

Now here is where it gets really interesting... Those extreme introverts are slowly surfacing.
How, why?
Because ... technology, that's why.
The internet and social networks like Facebook and now our beloved steemit have provided them with a communication medium that they had been lacking throughout their existence.
Imagine a 16th century introvert.
He was a complete outcast, a loner, a weirdo, living alone in an isolated cabin in the middle of nowhere. I imagine him reading his favorite books under a candlelight.
Now back to the present.
He has access to all extrovert knowledge even though he is not one of them.
He can communicate comfortably (perhaps not verbally but by typing) without being blocked by extreme nervousness.
He can be very productive and creative. He doesn't have to interact with anyone to obtain tools. He can do all the work remotely at home on his computer.

Now you are probably thinking, what a load of bs. Introverts are Homo Sapiens that just slightly deviate from the norm. To which I answer: but not by choice. Not because they were raised to be different. Rather, it's in their genetic makeup, in their DNA.
But how different should the DNA be to qualify as a different species?
A few genetic alterations here and there would definitely not make the cut. More than a few then? Many more? How many?
You've probably heard that chimp DNA only differs by 4% from Homo Sapiens DNA. And they are most definitely a different species.
Where does one draw the line?
I'm not a geneticist and I can't answer that.
But I know this: we are all different, but some of us are more so than others!.
You can quote me on this one day.