It really varies for me... depending on what I'm doing I can spend between 30 minutes and 8 hours online per workday. As I work for the government, almost all entertaining sites are blocked (i.e. Facebook), and I get dirty looks from my boss when I check my Gmail account (even though a few of the people I deal with for work use my personal email to contact me). Mostly, though, I spend my day reading old archaeology reports or looking at old bones, so not that much internet time...