Wikipedia is a rapid and invaluable encyclopaedic source on almost any conceivable subject. It is not trustworthy, but serves as a summary on most subjects. It tends to focus excessively on American memes and popular fiction and culture, at the expense of objective truth or history. Its primary editorial criterion is by reference to outside publications, which may be dubious, whereas first-hand evidence may be deleted as uncorroborated.With regard to modern, fashionable, political or contentious events and judgements, trolls frequently assert conspiracy theories and nonsense on its pages, which are then taken down by validators as not properly sourced.