The first comment represents complete ignorance. Cyclists have full legal right to the whole road. We should ride to the right IF it's safe to do so. We should claim the whole lane when it would be unsafe for a car to pass us. As Aaron says, we sometimes must take the lane because the road surface is dangerous. Cars don't feel the impact of potholes, glass, and other debris which can catapult us from our bikes, puncture our tires, or put us in the path of car doors and people turning out from side streets.