Interactions—such as posts—end up being driven by economic considerations. For instance, posting music and movie reviews in a specific community is currently the trend.

I call those things "distractions"... Now and then we have a big curation project supporting a specific community, and a bunch of users become "experts" in the matter, posting in those communities... As the focus/money moves to other topics, those creators move too...

Not sure how that's good for the longevity of the chain (and authors themselves), as they rarely create bonds on those posts... It can happen, but it's usually shallow...

Anyways, it's good to have diversified communities and people sharing their personal thoughts, views, opinions... That's how we grow... ;)