Promoting comments to answers
In trawling through the Unanswered Questions page, I've come across more than a few questions where the original poster has answered his or her own question, either by editing the question itself or by posting it as a comment. Here's an example: Nodejs - .node_libraries/ for www-data.
Currently, there's no way to get the user to make that answer an actual answer as recognised by Stack Overflow and accept it. I'd like to see a way to prod either the user or a moderator into moving that answer into the answers section and accepting it, taking it off the Unanswered Questions page.