I was watching a youth game this weekend, where an indirect free kick was called. One player on the attacking team stood next to the ball and lightly touched the ball, and his teammate kicked it into the goal. The opposing coach argued that the goal shouldn't count but the ref ruled it was a good goal. It sounds to me like the ref ref made the right call. My understanding of the rule is that the first player only needs to touch the ball; the ball doesn't need to move a full rotation or anything, does it?
The old rule was that the ball had to move its circumference before it was in play. Since this is about two feet...and the rule was often ignored in practice...FIFA changed the rule: now, the ball is in play when it is "touched and moves," which far more workable: since the act of touching the ball will invariably move it, as a practical matter we don't have to concern ourselves with measuring distances, but need only observe the first touch. If the coach grew up under the old rules, he may well be confused by the rule change.