I've been following Numenta for years now, I'd sometimes jump into the IRC channel to chat a long time ago. The learning material back then was very limited, but it has gotten significantly better.
The reason my interest in this project fluctuates is because I'm never really sure if I am researching the latest version of the theory. Or which code bases are updated to reflect the latest theory. I recall jumping into the IRC a couple years ago asking questions about some code on github, and someone replied "Don't reference that, the theory changed and it hasn't been updated yet".
It seems to me that in order to be aware of the current state of the theory, and whats changed you need to be constantly monitoring the site and mailing lists.
I'd rather see some kind of versioned/source controlled spec of how the neocortex functions(Or at least the current consensus). A timeline of changes to the theory and then have it referenced in the code samples somewhere. Just some kind of confirmation that what I am working with is an implementation of latest research/theories.
All I am getting at is that no one wants to work off old research. Maybe just a new time stamped white paper every month or two so I know it hasn't gone stale.
Anyway, that's kind of how I've felt about Numenta/Nupic over the years.