Thanks, @sam.
I’m looking at using Discourse as a MOOC platform. It’s worked well to run my classes this summer. I’d have people reply-as-linked topic to the assignments (aka “quests”). And I’d “like” their topic when they got it right. I think now that with badges, I can not only give them badges when I approve their work, but also have more complicated ones that, e.g., let people who have achieved a badge give it to someone else.
And it looks like the solved plugin will get me moving forward. Thanks!