The following solution is supposed to clarify the controversial incident having occurred in World Cup 2010 semifinal match between Uruguay and the Netherlands presented in this blog post.
Assistant Referee Bakhadyr Kochkarov of Kyrgyzstan allowed the goal scored by Wesley Sneijder and did not rule it as an offside offense. It is clear that Robin van Persie, another Dutch forward, was closer to the goalline than the second last defender meaning that some criteria have to be checked to determine whether he was positioned in active or passive offside at the moment when Sneijder touched the ball.
In the context of Law 11, the following defitions therefore apply since 1 July:
"Interfering with play" means playing or touching the ball passed or touched by a team-mate. - Van Persie neither played nor touched the ball. Therefore this does not apply for this specific situation.
"Interfering with an opponent" means preventing an opponent from playing or being able to play the ball by clearly obstructing the opponent's line of vision or challenging an opponent for the ball. - Van Persie did not obstruct goalkeeper Muslera's line of vision, the shot never was optically invisible for the goalkeeper. He made a movement with this feet that could be identified as a form of irritation for the goalkeeper who had to wait a bit to see whether the Dutch striker would deflect the ball. However, this is not of any interest anymore since 1 July. Furthermore, van Persie did not challenge any opponent for the ball.
"Gaining an advantage by being in that position means playing a ball a) that rebounds or is deflected to him off the goalpost, crossbar or an opponent having been in an offside position (not applicable for this incident) or b) that rebounds, is deflected or is played to him from a deliberate save by an opponent having been in an offside position." - As van Persie did not play the ball, this criteria can be ignored.
In conclusion, the correct solution is: No Offside.
How come that 61 % of the votes in the poll favoured the solution "Offside"? Probably, because it was classified as interfering with an opponent until the start of July 2013! Interfering with an opponent meant, until this point of time: "Preventing an opponent from playing the ball by clearly obstructing the opponent's line of vision or movements or making a gesture or movement which, in the opinion of the referee, deceives or distracts an opponent". Van Persie obviously distracted (or irritated) Muslera by his movement having been in an offside position so that before 1 July 2013, this allowed goal was a mistake. In 2010, Kochkarov should have flagged it as offside.
Now one can certainly ask to what extent these amendments to the Laws of the Game are compatible with common sense. Ignoring the new version of Law 11 for a moment - should not this goal be an offside goal at any rate?