If you can't open the video or it's too scratchy to follow (it is sort of a low-quality clip), I'l summarize: things were scoreless in the early going of today's match between SS Lazio and SSC Napoli. From a Lazio corner, former Bayern and current Nationalelf striker Miroslav Klose got up to try to head the ball into the net. Right in the mouth of the goal, Klose lunges at it with his head and barely misses. But the ball then ricochets off his hand/wrist/forearm and into the goal. The officials didn't quite see what happened (it was a very quick play) and signaled a goal for Lazio.
But Miro has long been known as an honorable man of high character. He showed what he was made of again today, approaching the referee and letting him know that the play was, in fact, a hand-ball. The goal was waved off, the scores were reset at 0 apiece, and Napoli went on to win through a Cavani hat trick.
Hard to say whether it would have impacted the match. You could say that Lazio might have been able to sit back and defend if they had a 1-0 lead, but it looks like Napoli was much better throughout. Either way, you can't fault Klose for doing right by his conscience.