articles from sources such as Wikipedia and Wikinews, to ensure that the content remains unchanged for review. A reviewer can then view the cited revision, the current revision, and the differences between the two. Presentation Blog entries are usually laid out as follows: Title Date Body Comments, permalink, and what category the entry was posted to (known as metadata) Permalinks are usually denoted by text link (i.e. "Permalink" or "Link to this Entry"), but sometimes a symbol may be used. The most common symbol used is the hash sign, or #. However, certain websites employ their own symbol to represent a permalink such as an asterisk, a dash, a pilcrow (¶), a section sign (§), or a unique icon. Permalink detection Permalinks can be indicated within the HTML of a page so as to allow automated browsing tools to detect the permalink and use it for linking instead of the stated URL. The link element should include the following attributes: <link rel="bookmark" href="http://example.com/bookmark/123/" /> See also Persistent identifier Deep linking Digital object identifier (DOI) Persistent uniform resource locator (PURL) Uniform Resource Identifier (URI) URL mapping Perma.cc References External links Cool URIs don't change - Tim Berners Lee Choose URIs wisely Link type "bookmark" cite-as: A Link Relation to Convey a Preferred URI for Referencing Identifiers Unique identifiers ja:Uniform Resource Locator#パーマネントリンク