Itamar Tzadok

Mark, maybe a course format plugin could reduce core changes significantly or even eliminate them. Have you considered such approach?

Maybe it's time to add more adjectives to the post rating:

• Entertaining - posts that make you laugh (group: Particularly Entertaining Moodler (PEM)).
  
• Artistic - posts which please you aesthetically (group: Particularly Artistic Moodler (PAM)).

Such ratings could allow a finer appreciation of the value of the post. The groups and badges for these ratings are nice to have but not necessary.

Add that to the calculation ...

Some may find it useful to see that others are of the same opinion. Some (myself included) mark useful posts that make them laugh. You actually put it in the best tautological way: useful means useful, that's it. It is just that this "it" can be many many things and very likely not the same thing for everyone.

The use case is such that he/she is the OP. OPs typically don't receive an email with their post. And even if they could receive such email, I for one would not opt for it. We have enough emails as it is.