Role of XFN in social networking

XFN (XHTML Friends Network) is one simple way to represent human relationships using hyperlinks. In recent years, blogs and blog rolls have become the fastest growing area of the Web. XFN enables web authors to indicate their relationship(s) to the people in their blog rolls simply by adding a ‘rel’ attribute to their <a href> tags, e.g.:
<a href=”” rel=”friend met”>…
XFN puts a human face on linking. As more people have come online and begun to form social networks, services such as Technorati and Feedster have developed ways to show how the various nodes are connected. Such services are useful for discovering the mechanical connections between nodes, but they do not uncover the human relationships between the people responsible for the nodes.
XFN specifies the relationships between individuals by defining a small set of values that describe personal relationships. In HTML and XHTML documents, these are given as values for the rel attribute on a hyperlink.
XFN allows blog authors to indicate which of the blogs they read belong to friends. Using XFN values, which can be listed in any order, people can humanize their blogrolls and links pages, both of which have become a common feature of blogs.
In sufficiently modern browsers, authors using XFN can easily style all links of a particular type; thus, friends could be boldfaced, co-workers italicized, and so on. It is also the hope of the authors that this practice becomes widespread enough to allow the creation of a service that charts personal (as opposed to purely mechanical) links between blogs and the people responsible for them.
You maybe aware that the roles of a link defined by A or LINK are specified via the rel and rev attributes.
XFN provides the basis for a world-wide distributed network of personal connections.. The advantage of a Friendorati-style network is that it allows every individual to fully express themselves through personal blogs and web sites. Normally expressions are allowed to limited degree permitted by a proprietary service’s user interface.
Commercial services like Amazon, now currently ask users to manually register all their friends in order to prepare  a “wish list” and other information sharing simpler. This will make simply to crawl XFN relationships on the open Internet. This would allow a user to enter the URL of their site, and let the service  analyze XFN relationships to build a list of friends through programs.
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