You can submit your questions via Google Moderator where others can vote up your questions and you can submit or vote on other questions. The goal is to get the most important questions answered by Matt Cutts first by using this moderator system.
Matt Cutts wrote:
Every few months I take questions about search, how Google works, or search engine optimization, and record the answers on video. It's time to record some more videos! You can submit your questions here: http://goo.gl/d0pmp
In every batch, Matt Cutts and his team, find a way to make the video quality and answers better. If you remember, the first few were not done that great but as they do more and more, the quality keeps improving.
The YouTube channel now has over 8,750,000 video views. So clearly people are benefiting on some level from these.
Forum discussion at Google+.