Quora is full of it, and so is LinkedIn.
A shill asks "a question," followed by all these "answers," recommending a particular site, product or technique (that has a backer).
I have had to leave quite a number of forums, because they became completely taken over by Asian spammers; doing exactly this. They rendered the groups useless.
TBH: I did fall for it the first time I encountered it. It's a fairly effective technique, if done right.
I have not run into this kind of spam on SO.
There are a lot of "Kool Aid" threads, where folks get heavily invested in a technique or pattern, but those are legit, if somewhat tiresome.
Also SO is very specific and narrow (programming questions only), while Quora is very broad, so it's probably harder to moderate effectively.
Quora did have a points/credits system in the beginning but they removed it for some reason, and ever since then participation and edits were open to everyone which let the spam take over. They also have a faceless AI-powered moderation system that's often overbearing and wrong.
Though I'll say this -- it's hard to optimize Quora's feed, but once you do that by carefully curating the topics and the people to follow, Quora can be an incredible source of super insightful answers on niche topics. But it does take a lot of work, which is a barrier to many.
Their feed display mechanism needs a lot of work imo.
Like "Where do I start with machine learning?" often with bad spelling, or "Do you need to be very smart to become a programmer?" etc. By contrast, Reddit, the StackExchange sites and HN are a totally different league.
I don’t doubt that the good content is there. I think their algorithms just changed and now I don’t see it anymore. Not willing to put in the effort to figure out how to get an interesting feed again.
And at that point they had changed parts of the site so much I couldn't figure out how to subscribe to new topics because all of them were replaced by user-created topics/groups like on Facebook(at least that's how I understood it).