I welcome feedback and questions, and there are several ways to contact me.
One good way is to ask a question on our forum and invite others to answser. I read all the forum posts.
I have a couple people that help me answer questions, especially about the website, but also about Go questions. This allows me to spend most of my time making new lectures and problem sets. Please use this email to speak the them directly: firstname.lastname@example.org. I look at every email and every answer that goes through this email address.
For questions about a specific problem in the Training System, use the "Discussion" button. This helps us because the discussion page will show the problem with the same colors and orientation for everyone (most Training System problems shift colors and orientations around the board). Plus, you may find there that your question has already been answered.
If you want to contact me directly, send me a note at email@example.com.