Charlie - I'm the author and do plan another couple of blogs in this series. It's funny, I've been doing this for a while and only came across the concept of a "Niko Niko" calendar a few weeks ago. Convergent evolution.
I thought the big thing would be getting early warning on problems, but what I'm hearing is that the team really likes having a forum where they can express their sentiment anonymously and seeing how the rest of the team is feeling.
I think that second piece is more about having a common metric that can be tracked sprint to sprint.
I quite like the idea of the calendar, hadn’t come across that before. Has anyone used it and found it works?