Clever concept, but it took me a little while to figure out that the left and right margins were independently controlled by the radio buttons to the left of centre and the radio buttons to the right of centre, respectively.
I think a single group of radio buttons to control both sides would have made more sense.
Neat effect, but those little radio buttons are hard to click accurately. A nicely styled table running across the top of the article might do better (IANAD).
I love it. As newspapers discovered long ago, it's often much easier to read text that isn't a foot wide (less necessary eye movement).
yeah pretty neat. but then i thought, why not two scrollbars?
then I thought, why implement something so useless in the first place?
It's actually not useless at all. The human eye reads optimally at about 70 characters per line, more and the eye has to work harder to locate and skip back to the beginning of the next line, less and there aren't enough characters for your brain to successfully pre-scan the line. So, depending on your font size it is very handy to be able to adjust the column width to display approx. 70 chars a line.