I've seen in wordpress meta, XFN - XHTML Friends Network Do you have any idea what is it? why I should link to this link? http://gmpg.org/xfn/ Some social search engine they are talking about http://rubhub.com/main/
It's short for cross reference number I think. It's a way of keeping tabs of what link came from where and who. Col
The page you linked to explains everything. XFN is an acronym for XHTML Friends Network as is defined as a simple way to represent human relationships using hyperlinks. It's just an attribute added to your <a href> tags describing your 'relationship' with that particular link, how they are connected. Read the intro for more information. Hope that helps.
Link to who? If you mean why should you have a link in your meta section, well that is there simply to inform other people about what XFN is. It's just a form of advertising I guess. Personally I don't use the XFN attribute but that doesn't mean I'm going to remove the link from my blog. What difference does it make?