To recap:
You can publish anything you write in infinite social environments (Quora, Medium, LinkedIn, Wattpad, excerpts on Twitter and Facebook, etc.).
You can publish articles in infinite social environments and forge partnerships with publications to syndicate your content directly (content originally published on Quora can be syndicated into major publications like Inc, Forbes, TIME, etc., IF you facilitate it yourself by reaching out to someone on their syndication/partnerships team).
You can publish articles in infinite social environments, and publish them on a website/publication you own, and syndicate them to infinite publications you have partnerships with.
If you author an article on a major publication first, that article can be republished on your own social profiles (so long as you include a link at the bottom to the original).
If you author an article on a major publication first, that article can be republished on your own publication (so long as you include a link at the bottom to the original), allowing it to be syndicated to other publications you have partnerships with. Some publications are OK with this, some aren’t