As part of my job at SocialCops, I read and edit lots of content. Em-dashes are one of the most frequent issues I see. Everyone loves to use em-dashes because they're so powerful, but getting them right can be tricky.
PS. We're always looking to hire great content writers at SocialCops. If you're the sort of person who likes to read about em-dashes in your spare time, we'd love to talk to you. Check it out: https://jobs.lever.co/socialcops.