XFN (XHTML Friends Network)

A big part of Web 2.0 (over the last decade) has been a move toward the semantic internet, whereas each page is representative of data and it’s relationship… we are, in essence, “training” the internet itself.

XFN markup allows you to identify your relationships to other individuals on the links of your website or blog.

<head profile="http://gmpg.org/xfn/11">

HTML5: (removes the ‘profile’ attribute on <head> as such the updated convention is:
<link rel="profile" href="http://gmpg.org/xfn/11" />

Use in content:
<a href="http://www.skotfred.com/" rel="me">My other site</a>




DNS Prefetching

DNS is much like a phone book for the internet. For each domain name (or subdomain like ‘www’), there is an IP address that resembles a phone number. Getting the matching number for each domain can take some time and make your site appear slow, particularly on mobile connections. Fortunately, you can pre-request this information and speed up your site in most cases.

To enable a domains DNS lookup to be performed in advance of the request, you can add a single line to the <head> section of your page.

<link rel="dns-prefetch" href="//giantgeek.com" />

If you want to explicitly turn on (or off) this behavior, you can add one of the following, or their HTTP Header equivalents:

<meta http-equiv="x-dns-prefetch-control" content="on" />
<meta http-equiv="x-dns-prefetch-control" content="off" />

This is supported in all modern browsers:

  • Firefox 3.5+
  • Safari 5.0+
  • MSIE 9.0+

If should be noted that a similar method can be used to prefetch as page, but I will save that for a different article:
<link rel="prefetch" href="http://www.skotfred.com/" />