yes Lady, on weightwatchers you can 'earn' extra points allowance for exercise. Not loads of points but it can useful if you slip over by a point or 2.
45 mins of swimming (pretty constant swimming, not 10 laps and a half hour chat on the sides) earns 2 points
40 mins on a rowing machine is also 2 points (but obviously that will depending on how vigorous you are, how fit you are, how good you machine is etc).
45 minutes brisk walking is 2 points
30 mins gentle cycling is 1.5 points
30 mins strenuous cycling is 3.5 points