Perhaps Similar Worlds can implement a point system or one akin to it to incentivize engagement.

OMG. Let's also have parent conferences to keep parents or guardians informed about the progress of their little posters. And, maybe parchment certificates of achievement (suitable for framing) could be handed out, maybe quarterly(?) to recognize posters who reach engagement thresholds.

Note: "Icon medals" are already applied to accounts for reaching milestone comment numbers.