I definitely agree with Dirk about this being (darn near) "obligatory" before the first post/question. I would even go a little further and say that it should be part of the onboarding process or first 30-days of a new account opening, like a series of welcoming orientation videos (perhaps even via email).
I've been on Moz on and off for maybe 5 or 6 years but I never knew the Q&A section was so valuable/useful/helpful. All I ever really saw (or remember seeing) outside of the paid tools and MozBar was the Moz blog, WBF, and a little YouMoz. I just posted my first question ever this weekend. Had I seen this video years ago I would've been more engaged from day one.
All that said, I think the Q&A forum needs more visibility. More people should see this video. For 5 or 6 years I took my questions to Google instead because that was my conditioned response when I didn't know something about SEO. I feel it's so much better than just another blog post because here we have multiple people vetting the right answer or different approaches.
At this point, my first instinct is to query the Q&A section. I just think the link was burried a little too long for me to notice. Maybe putting a subtle, non-buried link in MozBar would be a good way to keep the community top of mind. Or a very small pop up speech bubble with a guided tour for people who visit the site often but never visit the Q&A section. Just thinking out loud here.
Good work! I'll definitely recommend this video to others. Really great point about following up quickly, btw! Thank you!