Prosecutor Andrew Edis, QC, told the Old Bailey the now-defunct Sunday tabloid was a small-sized newspaper in terms of content which allowed its editors to easily track where stories had come from.
He said the executives in charge of the "purse-strings" must have known what was going on among its reporters.
Mr Edis was opening the prosecution of figures such as former News International chief executive Ms Brooks and the Prime Minister's former communications chief Mr Coulson.
He told the jury of nine women and three men that a great deal of phone hacking went on at the newspaper, with celebrity victims alleged to include Jude Law and Sienna Miller, ex-home secretary David Blunkett, actress Joanna Lumley, and pop star Will Young.
The court heard the paper was also interested in the royal family, with alleged victims including Lord Frederick Windsor, son of Prince and Princess Michael of Kent, and Jamie Lowther-Pinkerton, former private secretary to Princes William and Harry, who recently became one of Prince George's godparents.
Mr Edis said private investigator Glenn Mulcaire, who was paid £100,000 a year, and then royal editor Clive Goodman admitted in 2006 to phone hacking.
It emerged yesterday that Mulcaire has pleaded guilty to three counts of conspiracy to commit phone hacking, along with a count of phone hacking
The tabloid's former journalists Greg Miskiw, James Weatherup and Neville Thurlbeck had also each admitted to conspiracy to illegally access voicemails.
He said: "News International was keen to say that phone hacking in the NotW was really limited to Mr Goodman. But this inquiry has proved conclusively that that is not true. Obviously it has, because it has secured the convictions of Greg Miskiw, Neville Thurlbeck and James Weatherup." He added: "The paper wasn't War And Peace. It wasn't an enormous document. It was the sort of document that if you were its editor you could actually take an interest in its content without too much trouble.
"What you are going to have to consider is whether these people were doing their jobs properly, in which case we say they must have known what they were spending the money on. They must have known, we say, where these stories came from, otherwise they would never have got into the paper."
Ms Brooks, 45, of Oxfordshire, Mr Coulson, 45, from Kent, former NotW head of news Ian Edmondson, 44, of London, and the tabloid's ex-managing editor Stuart Kuttner, 73, of Essex, are all accused of conspiring with others to hack phones between October 3, 2000 and August 9, 2006.
Ex-NotW and Sun editor Brooks is also charged with two counts of conspiring with others to commit misconduct in public office - one between January 1, 2004 and January 31, 2012 and the other between February 9, 2006 and October 16, 2008, linked to alleged inappropriate payments to public officials.
Former No 10 spin doctor and ex-NotW editor Coulson is also facing two allegations that he conspired with Goodman, 56, from Addlestone in Surrey, and persons unknown to commit misconduct in public office.
It is claimed that Goodman paid palace policemen for copies of Royal phone directories - allegedly authorised by Coulson - in a bid to get information on members of the Royal family.
Brooks also faces two allegations of conspiracy to pervert the course of justice, one with her former personal assistant Cheryl Carter, 49, between July 6 and 9 2011; and a second with her husband Charlie Brooks and former head of security at News International Mark Hanna and others.
The defendants, who deny the charges, are on bail. The trial continues.