Invisible elements for additional link text

Hi Guys, 

I requested one of our designers make our 'read more' links more descriptive to include things like 'read more about article title' and his response was to have; 

'<span>Read More <span class="invisible">about topic title</span></span>'

I know that the WebAIM guys are ok with invisible text for adding additional information for descriptive technologies, I was wondering what everybody elses opinions were.

Reference; http://webaim.org/articles/gonewild/#hidden 

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Christian Biggins