How can I mimic a social media type interactivity in Rise or in a SL block?

Easy solution... embed something that already has the functionality in Storyline... and you can add it to Rise as a Storyline block...so you have the functionality.

More complex solution. Make a Storyline block that has the functionality and add that as Storyline block.

Biggest issue in any of these 2 solutions is taking care of the comments section. As neither Storyline nor Rise provide real dynamic elements its hard to show comments of users when added dynamically. In real life comment sections posts are pushed down or on new pages. In either Storyline or Rise this feature lacks. You can make something like me Feature Request tool, but thats also hindered by the lack of real dynamic features in both Rise or Storyline.

Here you can find that one.
https://community.articulate.com/discussions/building-better-courses/feature-requests-overview-and-voting-system