There has been some accusations that Wikipedia has, in certain instances, a left-wing bias. I'm not sure how valid they are, but apparently the editors lean more left than right, or did. I'm not sure if and how Wikipedia has addressed this. Perhaps it's only a mild problem for Wikipedia, but it is a more serious one for academia, as peer review has failed at times because of the ideological monoculture. One can have all the checks and procedures, but if there isn't an attempt have some balance among perspectives of the reviewers, the process will likely be weak.