Summary:

When there is a ‘wall’ of three or more defenders, the attackers are not allowed within 1m (1 yd) of the wall; an attacker less than 1m (1yd) from the ‘wall’ when the kick is taken will be penalized with an indirect free kick.
When the defending team takes a free kick in their own penalty area, the ball is in play once the kick is taken; it does not have to leave the penalty area before it can be played.

Explanation:

Attackers standing very close to, or in, the defensive ‘wall’ at a free kick often cause management problems and waste time. There is no legitimate tactical justification for attackers to be in the ‘wall’ and their presence is against the ‘spirit of the game’ and often damages the image of the game.
The experiment where, at a defending team free kick in the penalty area, the ball is in play once it is kicked and does not have to leave the penalty area, has produced a faster and more constructive restart. Opponents must remain outside the penalty area and at least 9.15m away until the ball is in play. The same change has been made to the goal kick (see Law 16).