What Project X might mean: Ezra Klein officially said goodbye to The Washington Post last weekend and announced his move to Vox Media, the company that runs The Verge, SB Nation, Polygon, and Curbed, among others. Meanwhile, the Post’s publisher, Katharine Weymouth, defended the paper’s decision to turn down Klein’s proposal, saying it wasn’t guaranteed to be profitable and would have been a distraction, and noting that Bezos wasn’t involved in the decision. The Post also announced it would be hiring for a new data-driven journalism site as part of a broader expansion that includes a numerous other new hires and several revamped sections.

Klein’s description of his new site was vague, but touched on the need to add more context, education, and explanation to news. Vox CEO Jim Bankoff talked to CNN’s Brian Stelter and Ad Age’s Tim Peterson about the business side of the venture with relatively few details, though he said reports of a $10 million investment are “way high.” Klein gave a few more hints in a Q&A with BuzzFeed — it’s not going to just be a bigger version of his Post site Wonkblog.

Gigaom’s Mathew Ingram said it’s fine that there doesn’t seem to be much structure yet to Klein’s new project, and CUNY professor Jeff Jarvis voiced his excitement at the prospect of Klein specializing in the “explainer” form of news. The Post’s Matt McFarland was also intrigued by the idea, outlined in a job description for the new site, of building “the world’s first hybrid news site/encyclopedia,” wondering why those two forms couldn’t be rejoined. Mark Potts, a former Post staffer, noted that the Post kicked around an idea for that kind of hybrid back in the late ’90s.

In a perceptive column, The New York Times’ David Carr saw Klein’s move as an indicator that digital publishing has come into its own, rather than serving as an additional platform for traditional media. “In digital media, technology is not a wingman, it is The Man.” He followed that up with a look at a few varieties of the new breeds of digital media operations. Likewise, media analyst Ken Doctor explained what seems distinct about the form of digital journalism Klein is embarking on, and here at the Lab laid out the economic reasons it’s becoming easier to start a new site. NYU’s Jay Rosen argued that Klein is leaving the Post’s supply-side logic to start something based on the “keep me informed” logic of the demand side.

The New Yorker’s George Packer was skeptical of the distinctiveness and quality of this new brand of digital journalism as Carr explained it, but BuzzFeed’s Charlie Warzel said that many media critics like Packer are missing the fact that tech isn’t just a smokescreen or accessory for a venture like Klein’s, but “the difference between a successful new media venture and a flop.” The Columbia Journalism Review’s Dean Starkman pointed out that we don’t know if Vox’s ad-based business model can translate from niches like sports and tech to the drier topic of public policy. Jack Shafer of Reuters also raised some cautions about the venture, arguing that with low costs of entry and a fluid talent pool, it’s not very well protected from competition.

Inside and Facebook’s mobile news aggregation tools: Two new entries into the now-crowded field of mobile news aggregation services were announced this week: Jason Calacanis, the tech entrepreneur who founded Silicon Alley Reporter, Weblogs Inc., and Mahalo, launched a new app called Inside, and Facebook announced it’ll launch a social news reader called Paper next week.

At the Lab, Staci Kramer has all the details on Inside in a thorough interview with Calacanis. The app is built around updates of 300 characters — about as much as can fit on the typical smartphone screen — summarizing a single source (with a link) on a news story. The updates will be human-written by a full-time staff of 15 and a crew of freelancers, and Calacanis stressed the value of human judgment in finding high-quality sources of original reporting and summarizing them intelligently. The app has enough money from the sunsetting Mahalo to run without ads for the first two years, but when it does add them, it’ll most likely go the native-ad route.

Gigaom’s Mathew Ingram highlighted a few of these points, and talked to Inside editor Gabriel Snyder (formerly of Gawker and The Atlantic’s Wire) about the opportunity in mobile news that “feels akin to 2002 and the web, when everyone knew the web was going to be huge but it wasn’t clear how people would get the news.” The Verge’s Nathan Ingraham described the app’s mechanics and pointed out that Inside faces the aggregation conundrum of saving people time but also delivering clicks to their sources. Kramer also reviewed the app, calling it promising but inconsistent, particularly in its organization.

Poynter’s Sam Kirkland noticed the word “curate” in Inside’s App Store description and explored the aversion that Inside, Circa, and other news reading services have to calling what they do “aggregation.” Kirkland argued that it’s time to reclaim aggregation as a term: “Aggregation isn’t always bad, but automatically framing unoriginal reporting as curation helps these news middlemen avoid debate about whether we should be troubled by their methods.”

Facebook’s Paper is on the other end of the aggregation spectrum from Inside: It’s an automated and human-selected feed of news and content from your Facebook friends and the loads of the public content that organizations post on Facebook. The Verge’s Dieter Bohn looked at the app’s interface, concluding that its more relaxed feel “stands in direct opposition to the high-volume, high-noise vertical feeds we’re used to on Twitter and Facebook.”

Josh Constine of TechCrunch argued that Paper’s combination of content selection through editors, automation, and your friends leads to a strong sense of serendipity, and Recode’s Mike Isaac said the app taps into a broader network of discovery than the standard Facebook experience. Mashable’s Lance Ulanoff noted that Facebook still isn’t creating its own content here. Gigaom’s Mathew Ingram, meanwhile, noted that the market for social reading apps is becoming packed, and Facebook runs the risk of Paper feeling “like a tabloid stapled together from items they’ve already seen in their news feed.”

Reading roundup: A few other stories that grabbed some attention this week:

— This week’s U.S. National Security Agency surveillance happenings: The Obama administration reached an agreement with tech companies allowing them to disclose some vague information about the number of user data requests they get from the government; it was an improvement over the current information blackout, but many privacy advocates still aren’t too pleased. The NSA was also reported to be using “leaky” smartphone apps, like Google Maps and Angry Birds, to collect user information, and U.S. Director of National Intelligence James Clapper obliquely referred to journalists as leaker Edward Snowden’s “accomplices.”

— CNN announced a partnership with Twitter and the social analytics company Dataminr that will allow it to spot breaking news stories on Twitter more quickly and efficiently. Gigaom’s Mathew Ingram explained why it makes sense on Twitter’s end, and Alex Weprin of Capital New York explained what’s in it for CNN.

— A growing backlash against the preoccupation with longform journalism crystallized a bit last weekend in a New York Times column by Jonathan Mahler using the failings of Grantland’s Dr. V story to critique the fetishization of longform. Instapaper founder Marco Arment explained why he eschewed the longform push to focus on substance rather than length per se. BuzzFeed’s Ben Smith broke down the backlash and explored some of the differences between longform done well and done poorly.

— The other shoe dropped at Patch, where new owner Hale Global had AOL lay off hundreds of staffers — possibly two-thirds of the editorial staff. Meanwhile, as the Lab’s Ken Doctor explained, GoLocal24 is doing its own national ramp-up of online local news.

— Finally a few resources and pieces to think on: Poynter’s Craig Silverman released a handbook for verifying digital content, particularly in breaking-news situations; NYU’s Jay Rosen gave some thoughts on how a networked beat structure might be built; and at Journalism.co.uk, Alastair Reid wondered if journalists are properly equipped to handle the massive amounts of data being released by organizations and governments around the world.