Yet another great article with words to live by. I only came across the term mastermind group recently when asked to join one. The concept is sound; enough breadth to cover many topics, not so many people it's inefficient chatter.
Great point on those closest often not giving good advice. I can recall one project I evaluated. The person had feedback from friends and was thus convinced they had the best idea executed perfectly when neither were the case. Her friends simply lacked the knowledge and experience to have a clue so they went with mindless encouragement.