The less inhibited that one feels emotionally, the more likely they are to honestly express themselves. But for some, any technological form of communication will always feel more shallow than an in-person conversation. Not all communication is word-based, and there are many important subtleties that are not fully conveyed through the medium (e.g.: body language, facial expression, tone of voice, gesture, etc.). For example, something as simple as placing a hand on another's shoulder at a specific moment could speak volumes.
There is also usually some level of anonymity. These two factors seem to lead to a sense of disconnection and disassociation. "Normal" people can say the most atrociously anti-social things when they aren't acknowledging that they are actually interacting with another human being who is equal to them. And on the Internet, a person can often remove themselves from a conversation at will and without consequence. A "cyberbully" never sees a person crying on the other end.
However, the inverse seems to be true as well. Sometimes we so thoroughly express our values before our personal characteristics or circumstances that two people who might be unlikely to engage in real-life end up having deep and meaningful dialogues. To me, "being social" is having the willingness to engage others, and "community" implies a sense of camaraderie, a harmonious interaction brought about by complementary temperments and shared goals. These things cannot be induced, and at best, can only be facilitated. In order for such things to be global, we would first have to individually realize that people are neither animals nor objects, and then take steps towards resolving the behaviors that attempt to reduce people to such.
A sort of selfish hedonism and objectification is reflected in and fostered by many aspects of society. Whether it be advertising that preys on people's insecurities, an oppressive work or school environment that demands both competition and conformity, or a government composed of a hierarchical structure enforced through punishment and reward, people are so enmeshed in that type of thinking-feeling-doing they might find it impossible to extricate themselves from it, even when presented with other options.
Thankfully, every group is built by individuals, and every individual is capable of contributing to self-empowerment, collaboration, and equality, independently of any and all labels. It is interesting to think of the types of features that a social media platform would need to embody these ideals.
I respect the people who run Neocities very much because they do not use advertising and they allow for a good level of personal customization. This takes care of several important issues, but it still feels like there is something needed...a certain level of dynamism...
By "entering and leaving" I assume you mean an indicator of whether or not someone is present at a particular moment, somewhat like a chatroom? That would certainly keep people from lurking. Haha!
Perhaps the idea of "likes" and "follows" could be reworked to more closely reflect human interaction? For example, what if instead of a "like", it was an "identification": You would have to leave a comment about what you specifically identify with in a post before you could mark it as "liked".
And what if, instead of "follows" or "friends", everyone with whom you've shared an identification was sorted into a "weighted graph" by how much you've interacted with them overall? In life, we are "closer" to some people more than others. This is natural, but the tool would also randomly present others with whom we haven't yet shared any identifications in order to keep it from becoming an "echo chamber".
Any metric that could be used to stratify into a hierarchy (like number of views) would be completely removed, and it would keep fluff postings to a minimum because the posts themselves are what you make connections through.
...Hmmm, this is an interesting topic to think about. Thank you for asking these questions.