The ads are through Google Ad Sense and are a primary means for funding North Carolina Woodworker. We generate approximately approximately a 1/4 of our income from them and that helps pay the bills for the website.
We have restricted inappropriate content, but what shows up in the ads is related to what is posted or commented upon in a thread at some point. Since this topic is brought up, it makes this ad appear more often.
Every ad we restrict limits/restricts our possible revenue.