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Millennials are the first generation to move left as they age
(www.abc.net.au)
Rules:
Be a decent person.
No racism, sexism, ableism, homophobia, transphobia, zionism/nazism, and so on.
Other Great Communities:
Be excellent to each other
This is important to emphasise. Older generations were, generally, in more of a bubble, it wasn't easy to spread word with the same reach and authority as national mass media before the Internet.
Similar situation with other communication advances, like the telegraph, which allowed news of the world and the people around a country to learn and co-ordinate much better than before.