Wikipedia has three core content policies, two of which make it easy to plagiarize inadvertently. No original research prohibits us from adding our own ideas to articles, and Verifiability requires that articles be based on reliable published sources. These policies mean that Wikipedians are highly vulnerable to accusations of plagiarism, because we must stick closely to sources, but not too closely. Because plagiarism can occur without an intention to deceive, concerns should focus on educating the editor and cleaning up the article.
Sources are cited using inline citations, usually in the form of a citation in a footnote (see Citing sources for how to do this). In addition to this, when quoting or closely paraphrasing source material, in-text attribution is almost always required – for example: "John Smith wrote that the building looked spectacular," or "Smith (2012) wrote that ...". The Manual of Style requires in-text attribution when quoting a full sentence or more. Naming the author in the text allows the reader to see which words rely heavily on someone else, without having to search in the footnote. You can avoid inadvertent plagiarism by remembering these three rules of thumb:
INCITE: Cite your sources in the form of an inline citation after the sentence or paragraph in question.
INTEXT: Add in-text attribution when you copy or closely paraphrase another author's words or flow of thought, unless…