rel-contact

rel contact

rel="contact" was introduced by XFN 1.1 in 2004 and is in broad use across various social network sites (see services with XFN supporting friends lists).

Much later (~2007, citation needed), a draft of HTML5 redefined rel="contact" slightly differently (currently: HTML 5).

Publishers should consider using the XFN 1.1 profile to explicitly specify the XFN meaning.

Parsers should assume the earlier, well established and in use XFN rel="contact" meaning unless they encounter a document explicitly labeled as HTML5 that also lacks a reference to the XFN 1.1 profile.

This issue has been documented.