The BLOCKQUOTE element is intended to set off a long quote inside a document. Traditionally, the BLOCKQUOTE element has been rendered as an indented block, with wider left and right margins (about 40 pixels each), plus some extra whitespace above and below the block. Browsers will likely continue this type of rendering, although you are encouraged to use style sheets to create such displays (with or without the BLOCKQUOTE element). For inline quotations, see the Q element.

A URL pointing to an online source document from which the quotation is taken. This is not in any way a mechanism for copying or extracting content from another document. Presumably, this HTML 4.0 recommendation is to encourage future browsers and search engines to utilize a reference to online source material for the benefit of readers and surfers.