Frequently asked questions about XFN.
At first it seems easy enough to simply put an XFN value directly on the hyperlink and be done:
<a href="http://d.example.com/2003/11/08.html#T2134"> David wrote about a new theory </a> ...
But the problem with this is that the hyperlink doesn't link to the person David, it links to a specific blog post. Thus what does it mean to be a "colleague" of a blog post, or for that matter, to have "met" a blog post? The first step is to separate the person from the post. It's already an established convention to treat blogs or personal sites as representing the person. Additionally, we can add some semantics with the use of the
<a rel="colleague met" href="http://d.example.com/2003/11/08.html#T2134"> David wrote about a new theory </a> ...
and now it's much more obvious where to use XFN:
<a href="http://d.example.com"> <cite>David</cite> </a> <a href="http://d.example.com/2003/11/08.html#T2134"> wrote about a new theory </a> ...
<a rel="colleague met" href="http://d.example.com"> <cite>David</cite> </a> <a href="http://d.example.com/2003/11/08.html#T2134"> wrote about a new theory </a> ...
Bloggers like to share with others (hence they blog). Bloggers like to share with others the list of other blogs and news sources that they like to read — blog rolls. Some bloggers even like to annotate their blogrolls with an asterisk "*" next to the names of folks that they have met. XFN is the logical next step. A way to annotate the links in a blogroll according to whether you have met the person (and thus know they really exist), whether you think of them as a friend (and thus imply a stronger recommendation for their site) etc. XFN is easy (just add
rel="met" to links to people you've met for starters), and helps you enrich what you've already built — no new languages or files needed. Edit your blogroll, type a few keystrokes, save/upload and you've joined the XHTML Friends Network. Welcome.
It's all a matter of updating your hyperlinks. The easiest thing to do is to keep your personal links in one or two places (like your blogroll or links pages) and then just update those when your relationships change, just like you would update them if your friends changed where they host their blogs etc.But what about all my old blog posts where I've used XFN in my links to people? If you moved to a different city would you worry about updating all your blog posts that talk about where you used to live as if it were home?
You don't need to worry about updating your old blog posts' XFN info at all. In fact, just like the example of where you used to live, your old blog posts simply reflect your relationships at the time that you wrote those posts. See the XFN Background document for more on mixing XFN and time based formats like blogs.
If you XFN your hyperlink to someone with
rel="acquaintance", you are saying that that person is your acquaintance, and by deliberately omitting the '
met' value, you are saying that you've never physically met. Therefore you have a virtual relationship with that someone.
In the same way, you can make someone your virtual "
friend" as well. You may eventually meet them in person, and then you would link to them with