Following is a draft policy
Because of the specialized form of reference that Wikiquote provides, many external links that would be appropriate for inclusion in a Wikipedia entry are inappropriate for inclusion in Wikiquote entries. Furthermore, most Wikiquote entries should have parallel Wikipedia articles on the person, media, or theme covered in the entry. The wider array of general-purpose external links can be added to the Wikipedia entry, making their inclusion here redundant.
Appropriate external links in a Wikiquote entry include a small number of external links to reliable sources that provide general information about the subject's quotations, speeches, and written works.
Because of their lack of reliability, external links to quote collections that do not provide citations or support for their contents are not permitted. In addition, links to collections of quotes which merely duplicate quotes already contained in Wikiquote's entry provide no additional information, and including them serves no purpose.