Another NSA back door to user data: There were numerous stories this week tied to the U.S. National Security Agency’s surveillance campaign and journalists’ efforts to report on it, the biggest of which was The Washington Post’s report that the NSA has infiltrated a link between Google and Yahoo’s data centers to collect data from millions of their users without the companies’ knowledge.

Google and Yahoo executives were livid at the news, and the NSA’s chief made a statement that, as Techdirt’s Mike Masnick noted, amounted to a non-denial denial. The Post’s Andrea Peterson explained why the NSA felt it needed a back door to tech data in addition to its front-door access, and David Holmes of PandoDaily argued that the revelation reinforced the continued importance of encrypting online data.

For the rest of the week, most of the NSA news was coming from Europe, where the agency was reported to be collecting data on 60 million phone calls in Spain, in addition to previous similar reports about France and about the phone calls of dozens of world leaders. U.S. officials claimed they got the French and Spanish records from those countries’ intelligence services, but support in Congress is showing signs of waning, as Senate Intelligence Committee chair Dianne Feinstein came out against the NSA’s surveillance program.

Sociology professor Zeynep Tufekci wrote that the issue at the core of the NSA story is not the fact that it’s spying on its friends and its own citizens, but that the distinction between insiders and outsiders that it relies on is collapsing. If your institution “relies on outsiders staying outside while you talk in jargon and acronyms with your fellow insiders, it’s time to look for a safety net and a harness,” she said. At The Atlantic, Bruce Schneier framed the story in terms of the ongoing struggle over control of the Internet.

Leaks, advocacy, and objectivity: There was plenty happening on the journalism side of the story as well. NSA chief Keith Alexander said that “we ought to come up with a way of stopping” news organizations’ publication of information from the leaked documents. In the U.K., Prime Minister David Cameron gave The Guardian a vague warning that essentially told them to exercise more “social responsibility” with the documents, or else. The Spectator’s Nick Cohen lamented the fact that other newspapers in Britain have attacked The Guardian as well.

There were three long, thoughtful pieces on the NSA leaks and journalism this week, all well worth a read: The first was by Guardian editor Alan Rusbridger, explaining why his paper is publishing information from the leaks and what its relationship with the British government has been like. The second was by NYU’s Jay Rosen, thinking through the question of why some major investigative stories stir the public and others don’t and concluding that “making knowledge public does not a knowledgeable public make.”

The third was an exchange between former New York Times executive editor Bill Keller and Glenn Greenwald, the blogger and journalist who has broken the leak stories for The Guardian. Much of their conversation revolved around the question of whether journalists should report from an openly declared political perspective (as Greenwald argued) or should maintain a professional form of objectivity (as Keller argued).

Blogger Andrew Sullivan said we need both styles but argued that Greenwald’s is inherently more honest. Likewise, Mathew Ingram of paidContent didn’t see advocacy and fairness as mutually exclusive. On the other hand, Hamish McKenzie of PandoDaily also saw the need for both, but emphasized the importance of impartiality: “Facts need context, but not immediate spin. We need the boring “impartial” reports as much as we need Glenn Greenwald.”

Twitter goes visual: As it approaches its initial public offering, Twitter made a significant change in its display of users’ tweets, showing pictures and Vine’s short videos in user timelines by default, without a click. As The New York Times noted, the change makes visual ads on Twitter much more prominent, positioning the company to capture more of the mobile ad market. Digiday’s Jack Marshall called the new timeline Twitter’s version of banner ads.

Mike Isaac of AllThingsD pointed out that the change has Twitter looking more like Instagram (which is owned by Twitter’s chief rival, Facebook). BuzzFeed’s John Herrman wrote that while Twitter will look more like Instagram, it will become less like Instagram — rowdier and more random, because of the lower threshold for interacting with tweets. The update, Herrman said, will also help Twitter make more sense to a broader set of users: “There’s an image, I’m going to like it is a series of events virtually every internet user is conditioned to perform and understand.”

Wired’s Mat Honan made a similar point and said it makes it easier to widely share a photo on Twitter than on Facebook. Slate’s Will Oremus celebrated Twitter’s new image-centric orientation, saying it finally gets the primacy of images over text on today’s web. Mathew Ingram of GigaOM compared Twitter’s metamorphosis to the web’s clumsy ad-centered shift from text to visual in its early days and wondered if it would alienate users.

Reuters’ Jack Shafer argued that social media platforms like Twitter aren’t too concerned with alienating their users, since those users have largely accepted that they’ll swallow every change in their terms of service in order to keep their access to a free service they’ve come to consider indispensable. “Everyone now knows that the ToS noose is designed to grow tighter and tighter until it turns customers into the service’s revenue-producing slaves,” he wrote.

Henry’s vision for the Globe: John Henry, the billionaire owner of the world champion Boston Red Sox, finalized his purchase of The Boston Globe late last week, then published a column over the weekend explaining his motivations for buying the Globe and his plans for the paper. “My every intention is to push the kind of boldness and investment that will make the Globe a laboratory for major newspapers across the country,” he wrote.

Here at the Lab, Boston journalism professor Dan Kennedy outlined four takeaways from Henry’s column, dinging Henry’s commitment to getting readers to pay for online news but praising his overall focus: “Henry articulates a vision in which journalism comes first — which is another way of saying the customer comes first. Too many newspaper owners have forgotten that.”

Om Malik of GigaOM echoed Henry’s case for the importance of local newspapers in the life of a city, while journalism professor Christopher Daly (another Bostonian) wondered how the Globe will cover Henry.

Reading roundup: A few other stories that cropped up on the journalism/tech beat this week:

— The trials of several of the principal figures in the phone-hacking scandal of News Corp.’s British newspapers (centering around the now-defunct News of the World) began this week, and three former News of the World journalists pleaded guilty. The jury has also heard evidence of numerous allegations in the scandal, including that the paper’s journalists hacked their rivals as a way of scooping the competition. Gawker has a good, quick explainer of the case as a whole.

— That phone-hacking scandal was what prompted the British press reforms that were officially passed and signed into law as a royal charter this week, after the rejection of a last-minute court challenge by the nation’s newspapers. Deputy Prime Minister Nick Clegg assured the public, however, that the new regulatory system is entirely voluntary for the press.

— The Knight Foundation released a report on nonprofit news organizations’ search for sustainability with extensive data on 18 nonprofits. Poynter’s Rick Edmonds and MediaShift’s Paige Cooperstein both offered apt summaries of the report, and Mathew Ingram of paidContent focused on the importance of diversifying revenue sources.

— Author Tim Kreider wrote a column in The New York Times decrying the practice of writing for free online, an argument to which many, including paidContent’s Mathew Ingram, objected. Writer Dan Lewis explored the ins and outs of writing for exposure, and author and journalist Laurie Penny explained the dynamics of writing for print alongside the web.

— Finally, The Huffington Post’s Ryan Grim and Jason Linkins did everyone who reads American political journalism a favor with their guide to decoding the byzantine language of anonymous sources in Washington. Even if you’re hardened veteran journalist, it’ll make you a smarter news consumer.

Photo of Keith Alexander testifying Oct. 29 (with protesters behind) by AP/Susan Walsh.