A large part of the reason HN is so distracting, is that usually, when you read it, you look at the front page and open everything that looks interesting in new tabs. So when you're using your browser for something productive, you see a tab open that you haven't had a chance to read, and you want to go read it. Solution? Firefox profiles. Start firefox with firefox -P work --no-remote, and use that for all your work related things, while your should-read-later-eventually-maybe tabs stay happily open in another profile.
echo "127.0.0.1" `sqlite3 ~/.mozilla/firefox/*default/places.sqlite "select url from moz_places order by -visit_count limit 100" | cut -d/ -f 3|sort -u| tr "\n" " "` | sudo tee -a /etc/hosts