This post is a little bit more on the advanced level. If you’re frustrated, ask us with an email or look at some lolcatz.

If you’re on Twitter, Pownce, or Plaxo Pulse, you are probably already part of the most unknown social network out there: XFN.

Nuts and Bones

XFN stands for the “XHTML Friends Network.” XFN is a microformat and a facet of data portability. It is a simple way to spice up your standard XHTML to add some powerful functionality.

The basic concept is that everyone adds appropriate tags to links of themselves and their friends on their website. With this information, a search bot can crawl the web following these specialized links and assemble a network. XFN could kill (or at least redefine) address books as we know them.

Become a Part Today

XFN is young. Well, it’s 5 years old. It’s still relatively unknown. Many people doubted its importance until Google revealed that it’s Social Graph API reads XFN data. The Social Graph API allows programmers to do exactly that: graph social networks. Rather than treat each user as a separate person, you can single out people.

This is important because it allows you to consolidate your online identity. Not all of us can get the jump on our preferred user name. All of us can use XFN.

A Simple Example

Let’s say one my digital business card, I want to add XFN functionality. I would take the code for all of the links on the page and add the rel="me" tag.

So a link to my twitter would become

<a href="" rel="me"></a>

except all on one line, of course. Rinse and repeat for all links relating to yourself.

And Why is This Important for a Job?

Well, right now, it’s not. It might never be important for your average job, either. For tech jobs, it’s one of those things that really opens a potential employer’s eyes. Especially if they employer knows anything about “Web 2.0.”

Most importantly, it has the potential to save work for you in the future and consolidate your online identity. With XFN, you might never have to re-enter all of your information every time you join a new social network. Just point it to one of your previous profiles, and it will crawl all of your online identities for the necessary information. There are already a few services that have the capability to do this or will be able to do this in the near future.