||Online knowledge production sites, such as Wikipedia or Stack Overflow, are dominated by small groups of contributors. How does this impact the knowledge production and its quality? Does the presence of some key contributors among the most productive members improve or not the quality of the knowledge, considered in the aggregate? The present paper considers 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 online knowledge production sites. The paper addresses such question by an extensive data analysis carried out on the datasets of two representative sites: Wikipedia and Stack Overflow. Results from the analysis show 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 decline on entropy, overall, and with increase in stickiness in the maturation phase, after an entropy peak is reached.