Named for the former stadium of Sunderland AFC, the Roker Roar was said to be worth an extra goal.

wikipedia: The name Roker Park will be always remembered for the passion and atmosphere that the fans of Sunderland AFC created, and it is such a testament to this that the noise of the supporters received its own unique name - 'The Roker Roar'.

Sunderland fans (disclosure-I am related to many and was married to one) generally seem to regard this as a good thing. Including the fan who posted this testament from an opposing team captain on the Sunderland message board.

But nothing I have ever heard equalled the intensity of that wild roar at Roker Park last week when Sunderland drew level with Tottenham in the 6th round tie.
As we fished the ball out of the net and the mad with delight Sunderland fans streamed on to the field, I began to realise what the man meant who coined the phrase "an ear splitting roar". What effect does it have on a player?
How would you feel if an over-whelming crowd of people watched over you as you did your job, all of them cheering and jeering and hoping that you would fall down on the job.
The wrath of such a hostile crowd hacks away at a fellow' nervous system, hounding his confidence and undermining his concentration and skill. The individual effect is a matter of degree with each player depending upon his temperament. The team effect is something harder to define, depending on the relationship and confidence the players have in one another.
A player grows with experience to understand this pressure. This does not mean that it doesn't effect him - it just affects him less. At times, too, according to his mood, he is more vulnerable. If he is having a bad spell of form the crowd can have a terrible effect on him.