Someone posted that method on HN not too long ago. It's meant to increase readability by helping the eyes distinguish one line of text from the next. It's ugly and a tiny bit distracting at first but it really does work. Just give it a try. I zipped through those 2 paragraphs really quickly. I think it's Javascript based.
It's based on this: http://www.beelinereader.com/ by the looks of things (there's a beeline.min.js script included at the bottom of the page).
It looks very weird, but I can believe that it might improve reading speed.
It seems quite readable to me, although rather ugly.