The content production for this site is organized into two-week sprints ala Agile/scrum, each with a theme. At the end of each sprint, subscribers receive an email with that sprint's retrospective. The posts for the current sprint-in-progress are here:
I have a list of themes I'm considering doing sprints on. The next sprint is generally chosen during the current sprint. Email subscribers will be the first to know what the upcoming sprint theme will be.