re: Stealing... How effective?

Stealing puts pressure on the fielding team. What does a pitcher do when a runner is on first? Have you ever seen a pitcher miss the throw to 1st? Where does 1B play when a runner is on 1st? If you get your leadoff hitter on base, and he happens to be one of your better baserunners, you steal 2nd and can score without a base hit. The fielding team may also shift alignments to be in position to make a play at home. When a team shifts players, they are conceding some part of the field.

When you think about it, SB's is usually one of the offensive stats with a positive success rate or above 50%. Freeman and Fraley steal bases with ~75% success rate. This is why a team with great pitching and a solid defense will typically be in a position to win games. They can generate enough offense to win those close games.