Canary Chrome in OSX. It's been stuttery in every browser I've used, in multiple OSes; I've been on the site a couple times in the past for other posts (I think most via HN). To clarify: it doesn't crawl, but it's not smooth.
Looking at the profiler in Chrome, I'm not seeing any unnecessary events while scrolling between things - maybe it's a transparency somewhere instead? Removing a handful I could find did speed things up, though I probably missed a few. Browsers are still lame at those, unfortunately :/
Which browser and OS are you using? Scrolling isn't slow in webkit for myself, but I'd be happy to dig in and make it smoother if it's an issue.