||Online knowledge production sites, such as Wikipedia and Stack Overflow, are dominated by small groups of contributors. How does this affect knowledge quality and production? Does the persistent presence of some key contributors among the most productive members improve the quality of the knowledge, considered in the aggregate? The paper addresses these issues by correlating week-by-week value changes in contribution unevenness, elite resilience (stickiness), and content quality. The goal is to detect if and how changes in social structural variables may influence the quality of the knowledge produced by two representative online knowledge production sites: Wikipedia and Stack Overflow. Regression analysis shows that on Stack Overflow both unevenness and elite stickiness have a curvilinear effect on quality. Quality is optimized at specific levels of elite stickiness and unevenness. At the same time, on Wikipedia, quality increases linearly with a decline in entropy, overall, and with an increase in stickiness in the maturation phase, after an entropy elite stickiness, quality of content peak is reached.