Activity

The purpose of the reaction would be to record a kind of agreement or acknowledgment.
That way, Veritula could show ‘pending’ criticisms to users, say – ‘pending’ in the sense that they haven’t responded to those criticisms. So in addition to revising or counter-criticizing, they get a chance to accept a criticism without it remaining in a ‘pending’ state.

Posting arbitrary emojis doesn’t achieve that purpose.