For most people added salt is not bad. Salt can raise blood pressure but not by much. It is estimated that 8 to 15 grams of table salt per day is optimal (= 3 to 6 grams per day sodium). Table salt has the chemical formula NaCl = 39% sodium and 61% chlorine by weight so 10 grams of table salt contains 3.9 grams of sodium. One teaspoon of table salt weighs about 5 grams which means 2 grams of sodium.
It turns out that salt is not bad for you after all. Check out this great video.
This video discusses what is most likely the best study ever done on salt intake.
Basically these studies show that lower salt levels result in higher mortality rates - even for people with heart disease.
Another very insteresting WIL (What I Learned) video.