The Health Physics Society (HPS) conceived of the idea of an online "Ask the Experts" (ATE) feature in 1999 when the Society created its website. ATE features are popular now, but at that time it was a novel idea, so there was no assurance it would succeed. Now 20 y later, the HPS considers its ATE feature a success and the most valuable service the Society offers for the public. Nearly 13,000 questions have been submitted to the feature. They come both from members of the public and from health physicists. All have been answered personally by radiation safety experts. While it is important to answer questions personally, it is recognized that the most far-reaching impact of the feature is the written material on the ATE section of the website, which is provided for people searching for answers to their concerns and questions. Posted material includes frequently asked questions, summary papers on topics of interest, and links to other pertinent information. This is in addition to answers to a select group of submitted questions. To enhance the information search, all postings, including answers to questions, have headlines. These serve as keywords that facilitate website searches. The feature, managed by one lead editor, 20 topic editors, and more than 300 experts, draws over one million visitors per year. This statistic suggests that a substantial number of people are finding answers to their questions on the site and, therefore, do not need to submit personal questions. ATE editors have learned much about effective interaction with questioners, especially members of the public. Most important, answers should show compassion, present the bottom line first, be brief, and use plain language. Heavy reliance on peer-reviewed documents adds to the credibility of the information. Questions from the public cover a wide range of subjects; however, by far the most frequent deal with medical exposures, especially computed tomography procedures. Other questions deal with a wide range of concerns including products from Japan, granite countertops, radon, smoke detectors, luggage and whole-body scanners, and radiation exposure from airline travel. Another major concern is exposure to nonionizing radiation sources such as cell phones, radar, ultraviolet radiation, lasers, and power lines. Examples are provided of the most intriguing questions that have come to the ATE feature and the answers provided by the experts.