I do the same on the Phoenix light rail; This site's layout performs really well on mobile devices; Loading a beast like Digg on my N900 would make me twitch for kill -9.
Its a better experience on some phones than others; "Surfing the web" in Blackberry's browser is closer to "drowning the web" and rendering nothing correctly.
On a bus for 30 minutes? Use the phone to browse HN. etc