It took 40 days, heard 184 witnesses, cost the cost the taxpayer £855,300 and, according to a survey published today, has been tweeted about by UK journalists in the final quarter of 2011 more than the Eurozone crisis. It is, of course, the first module of Lord Justice Leveson’s inquiry into the culture, practices and ethics of the press.

For some, the Inquiry has presented the British press with an opportunity for a shake-up not dissimilar to that triggered by the Calcutt Report of the early 1990s. Guardian editor Alan Rusbridger praised the Inquiry for triggering a more nuanced look at regulation and statute. Others were less keen: Northern and Shell boss Richard Desmond called it “probably the worst thing that’s ever happened to newspapers in my lifetime”.

Leveson has learned a lot in the past few months. For one, the Inquiry has hammered the last nail into the Press Complaints Commission’s coffin. Harry Potter author JK Rowling called it a “wrist-slapping exercise at best”. In the same week, the  father of missing toddler Madeleine McCann suggested “repeat offenders” of incorrect coverage should lose their privilege of practising journalism. The editor of the Daily Express, Hugh Whittow, went so far as to suggest that one of the reasons for the paper withdrawing from the PCC was because it failed to stop the tabloid publishing defamatory articles about the McCanns.

Criticism also came from the Inquiry team. Counsel Robert Jay QC put it to ex-PCC director Tim Toulmin that the self-regulation body had failed to “test the boundaries of its powers” by choosing not to question former News of the World editor Andy Coulson after he resigned from the tabloid following the 2007 convictions of Clive Goodman and Glenn Mulcaire over phone hacking. Toulmin rejected the suggestion.

But PCC chairs past and present repeated that the body had been criticised for failing to exercise the powers it never had. Former chair Baroness Peta Buscombe argued that the body did not have investigatory powers to summon editors to give evidence under oath. She noted that broadcast regulator Ofcom cannot “deal with crime, nor should it”, and that the rest of the world “would kill” for the British press’s system of self-regulation.

“It is as if you say to the police ‘you are useless because you can’t stop crime’,” her predecessor, Sir Christopher Meyer said. “These are ridiculous arguments.”

The fear of statutory regulation is also alive and well. Times editor James Harding expressed concerns that a “Leveson act” would have a “chilling effect” on press freedom and make reporters submit to political influence. Private Eye editor Ian Hislop perhaps put it best when he said, “if the state regulates the press then the press no longer regulates the state.”

Meanwhile, current PCC chair Lord Hunt warned that “the road to parliamentary hell is paved with good intentions”, adding that there were“very strong views” in parliament that there should be tougher limits on the power of the press. Britain’s “much envied” press freedom, he said, was the country’s “greatest asset”.

It was left to Daily Mail editor Paul Dacre, never one for timidity, to throw the debate wide open with his suggestion of a press card system. He suggested transforming the country’s “haphazard” into an “essential kitemark for ethical, proper journalism”, with cards denoting “responsible” journalists. How this would translate in the online world of citizen media, however, was a question left unanswered.

Though not directly in Leveson’s remit, libel was one area flagged as in dire need of a revamp. Index CEO John Kampfner and English PEN director Jonathan Heawood flew the flag for the Libel Reform Campaign, arguing that it would be a “tragedy” if the Inquiry’s ongoing work inadvertently delayed the insertion of libel into the Queen’s speech in May. FT editor Lionel Barber also alluded to the “chilling effect” mammoth libel costs have on pursuing a story, while alternative, cheaper means of resolution were proposed by several witnesses.

The Inquiry has also unearthed some misdemeanours. James Harding was recalled to discuss an instance of a reporter at his paper using email hacking to reveal the identity of anonymous police blogger, NightJack, in a 2009 story.  The controversial printing of Kate McCann’s diary without her permission was also referred to more than once. Former News of the World news editor Ian Edmonson was quizzed about extracts of the diary that appeared in the paper in 2008, contradicting claims made by former editor Colin Myler that Edmondson had sought permission to publish from the McCanns’ spokesman, Clarence Mitchell. Asked if he had led editor Myler to believe he had “made it clear” to Mitchell that the paper had the whole diary and planned to publish parts, Edmondson replied: “No.”

Page 3, a mainstay at the Sun since the 1970s, has also proved contentious. Women’s groups said the feature existed “for the sole purpose” of women being sex objects, while Sun editor Dominic Mohan claimed it was an “innocuous British institution” that celebrated natural beauty and represents youth and freshness. He argued that the Sun speaking out against domestic violence in 2003 and raising awareness of cervical cancer screening following the death of reality TV star Jade Goody in 2009 were proof that it was not a sexist tabloid.

The battleground of balancing privacy — “for paedos”, according to Paul McMullan — and public interest is an area we seem less clear on than three months ago. Leveson heard on more than one occasion that there may be a public interest in exposing hypocritical behaviour of celebrities who are “role models”.  Former News of the World chief reporter Neville Thurlbeck defended his splash on David Beckham’s affair with Rebecca Loos, noting that the footballer had cultivated and marketed an image of having a fairytale marriage. Heawood argued that there was a difference between a harmful publication in a newspaper and “real intrusion”, citing JK Rowling’s testimony of a slipping a note into her daughter’s schoolbag as “tresspass”.

The Internet is also an issue keeping Leveson — and newspaper editors — up at night. Mohan called for a level-playing field between print and online, claiming that the combination of an over-regulated press with an unregulated internet was a “very, very worrying thought”. Mirror editor Richard Wallace suggested  ”legitimate” online news providers — whoever these may be — would want to join a new regulatory body because “it gives them a lot of cachet”. Meanwhile, media lawyer and commentator David Allen Green urged the Inquiry not to view bloggers and Twitter users as “rogues”, adding that social media users often act responsibly and regulate themselves by being transparent.

There is much to be done before Leveson makes any recommendations. In his next module he will examine the relationship between the press and police before delving into the mingling between the press and politicians, a union repeatedly lamented during module one.  Leveson has said he does not wish to become a “footnote in some professor of journalism’s analysis of 21st century history”. If the first module — and the Twitter attention — are anything to go by, it is doubtful he will.

Marta Cooper is an editorial researcher at Index on Censorship and leads coverage of the Leveson Inquiry. She tweets at @martaruco