Every email sent carries an easy to filter subject line as well as a descriptive title - so I can quickly see what's what. In addition, I feel as though I know Dave because he has time to add comments to almost every piece.
Random broadcasts can take the place of a regular monthly ezine.
You send articles as you're done writing or compiling them as opposed to meeting a single deadline. You can use random broadcasts as a way to stay in touch with your subscribers between scheduled issues. Point out to your members that the emails will be generally shorter than a regular edition of your newsletter. If your members aren't into it, don't push it. You may want to run both concurrently for awhile to see which format gets the most support.