I do think you are right about the rest as it applies to Twitter and Facebook.
There's been an awful lot written about all of this over the years, much of it overly simplistic and some of it just straight-up wrong; we all want to believe that we're just plain smarter than the ancients, even when those ancients were us.
If you're interested in (ahem) digging into this, start by searching for things like "Digg voting network".
Social networking was a thing. Social networking, link aggregation, discussion boards—it’s like pouring milk, hot sauce, and vodka into a vat to get Social Media.
I'm convinced he was paid to post stories to drive traffic to sites.
Of course I don't have evidence to support this. It was over 20 years ago.
Yep, some personalities on Digg had their groupies and if they posted something, all their followers would vote it up the listing, in effect the post was influenced.
That's when I bailed because genuinely interesting stuff not posted by the 'right' people had no chance of exposure.