The contrast ratio is 5.57:1 well above the 4:5:1 requirement. It seems that they're using Adobe Clean Light ( Helvetica Neue Light as a fallback). This must be the source of your readibility problem. Depending on browser/platform font-weight: 300 can be a huge problem.
You hit the nail on the head: The font-weight:300 is killing the readability in Chrome on Windows. When I toggle it off the text becomes readable.
I don't know what this 4:5:1 requirement is, but it also looks better to my eyes with the color:#444 toggled off so I get black text. But it's not as huge a difference as turning off the width.
The "4.5:1 requirement" can be found in the Web Content Accessibility Guidelines (WCAG) 2.0, part of a series of Web accessibility guidelines published by the W3C's Web Accessibility Initiative:
[1] http://juicystudio.com/services/luminositycontrastratio.php#...