In the English version of the online encyclopedia Wikipedia, notability is a criterion to determine whether a topic merits a separate Wikipedia article. It is described in the guideline "Wikipedia:Notability". In general, notability is an attempt to assess whether the topic has "gained sufficiently significant attention by the world at large and over a period of time as evidenced by significant coverage in reliable secondary sources that are independent of the topic". The notability guideline was introduced in 2006 and has since been subject to various controversies.