Verdana is a bit dated (it still looks good, but it's very reminiscent of early 2000s web design, as it was one of the few fonts that looked good without antialiasing on a 640x480 or 800x600 display), but I'd like to ask this of whoever gets tasked with refreshing HN's typography in the future: stick with a humanist sans serif. Don't go with Helvetica or another geometric sans serif.
Honestly, I feel like they could satisfy 90% of mobile users with just a few lines of CSS to make it a bit more responsive. Having to zoom, pan, and squint on my iPhone is so frustrating.