This is true and works as good advice. Some years back I was having my feedback call with HR person while I was being laid-off from the company, and one of the things she told me was my time spend on social networks and "other" websites not related to work (HN included). Reading between the lines here, IT is monitoring traffic and reporting it to managers at all levels. I was caught and, since then, I have never used my work device for anything but work.