Because IE is silly, and about as standard compliant as a 4 year old sweatshop worker making *brand name deleted* shoes.

Opera and Firefox know how to read CSS and W3C standards, thus it works.

Oh, and
// HTML this works as desired in MSIE 6 but has no position attributes

<a class="link" href="http://www.someurl.com>This is a Link</a>

class link has no positioning to it, so that might be it