I suspect there is something instinctual in us humans that seeks to create alliances - on a basic survival level, your odds go up if you are part of a group, right?
The Yi Ching or Book of Changes, said to be created by the Zhou people around 1000 BCE talks a great deal about the wisdom of creating alliances and of people working together, and how it creates the path to prosperity - so obviously people have been thinking about this for a long time. (.... not that tribalism is always a good thing of course, because when you have 'us', you also get 'them', but I digress ...)
(Way) Back in the day, there was only 'your people' against the vagaries of nature so there were no options. No trust necessary - blood was blood. To have a strong alliance or tribe, you have to believe that you are all on the same side, and perhaps virtual alliances are the modern way to find common ground and find out who you can trust to leap in with you to bring down that Mastodon!
Nowadays you can choose your tribe, not be born into it, but that has both up and down sides, mostly I think due to this 'trust' issue, and it is for sure harder to identify in modern day urban living.
Perhaps forums like this give you the TIME necessary to make decisions about which group you can trust, and thus want to be part of, to up your chances of survival ...?
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"It will be difficult at first, but then everything is difficult at first". Miyamoto Musashi