South had almost no values to mention so she or he passed as well and now the spotlight was on the west player and his team's result on the hand would depend mainly on his action.
The west hand has 16 high card points with a singleton diamond and at least three card support for each of the other three suits, so west has no interest in letting north play the hand at the one level without contesting the issue. The important question is what bid best describes this hand given the auction to this point, and the answer is that the hand is almost perfect for a re-opening double. This bid says to his partner, "I have few diamonds and can support either of the other suits if you choose to bid one, and have a decent playing hand". West is now in the position of being able to pass the double and thereby convert it to a business or penalty double. This is the action that says, "I can punish north in diamonds!"
How did this play out in real life? Only two east-west pairs defended one diamond doubled, getting 300 for down two once and 500 for down three the other time. This was the top score on the hand except for the pair who had the good fortune to defend against a three diamond bid for 800.
Two pairs bid and made three notrump making four, but all the rest of the field east-west languished in partscore for less than 200 points in all cases and less than average matchpoint scores. The moral is that if you make the proper bid on your cards you will likely do well on the matchpoint scale.
The re-opening double is a key aspect of the negative double convention because it "protects" a responder who, as in this hand, has great length in the opponent's suit. The responder playing the negative double convention cannot himself double for penalty because his double tells opener responder likes neither of the two previous bids but has strength in the two unbid suits.