1. While you're at it, read about @microformats's use of the rel attribute. xfn, rel-tag, rel-license, rel-nofollow, etc.

    http://microformats.org/wiki/rel

    To begin with, here's @diveintomark's explanation of the rel attribute. Read it. It's good.

    http://diveinto.html5doctor.com/semantics.html#link