Is it possible to edit a comment? I did not find any button for it.

It was a design decision to not allow editing comments via the web interface. The thinking being that comments on blogs tend to not allow editing, and allowing wiki-style editing by anyone would sort of defeat the purpose of comments.

I do think there is room to support more forum-style comments in ikiwiki. As long as the comment is not posted by an anonymous user, it would be possible to open up editing to the original commenter. One day, perhaps.. --Joey