One small amendment I think would be a nice touch is if there was an indicator to show how many responses there currently are to a profile post.
On a busy site this may not be that useful as recent updates may move out of the block within minutes or hours. However on smaller, quieter sites profile posts can remain in the block for days or even weeks.
This means even if there are daily users that visit the site index they may not notice that there are additional responses to a profile post without clicking on the interact button. If they've already done this once, there's no reason to do it again if they can't tell if there are new replies.
A subtle indicator that shows the current number of responses to that post, visible in the new profile posts block would let users know how busy or active that mini discussion thread is, prompting them to click the interact button and revisit it if there have been new posts since they last viewed it.
Additionally, if it's the first time a user as seen the profile post and it has a high number next to the interact button, it could indicate a popular/controversial discussion and encourage them to click the interact button and interact further, where they may otherwise have skipped over it.
Sample mockup with Syndols post at the bottom of this image: