A true pick basically leaves the guy that performed the pick out of the offense.
The picks you see in the NBA today (as popularized largely by D'Antoni) are more of a rub. It is ingenious because it forces the defenders to account for the player performing the pick because they can much more quickly and easily roll away for an open pass or cut.
These types of plays are much harder to defend and there's a reason every single NBA team is doing it now.