Most criticism of Wikipedia has been directed towards its content, its community of established users, and its processes. The principal criticism it receives concerns the online encyclopedia's factual reliability, the readability and organization of the articles, the lack of methodical fact-checking, and its exposure to political and biased editing. Concerns have also been raised about systemic bias along gender, racial, political and national lines. In addition, conflicts of interest arising from corporate campaigns to influence content have also been highlighted. Further concerns include the vandalism and partisanship facilitated by anonymous editing, clique behavior, social stratification between a guardian class and newer users, excessive rule-making, edit warring, and uneven application of policies.