here is the container div opacity 0.5

Here the content goes. z-index:0; opacity: 0.7;

The link above is not clickable in FF3.6, Chrome, Safari, Opera 10.5.
But this link is clickable in ie6-8, and Opera 9.
Make the content "opacity: 1;" to make the link clickable
Make the container div "opacity: 1;" to make the link clickable
relocate the absolute positioned div in the DOM tree to make the link clickable (even with adding opacity to it)

link to opacity specification: http://www.w3.org/TR/css3-color/#opacity
Yours faithfully, moony