BuzzFeed publishes nearly 400 posts per day. Earlier this year, however, the viral giant began quietly deleting an unknown number of three- and four-year-old listicles that “no longer met our editorial standards.” So what exactly are those “editorial standards”?

Speaking to an audience gathered at the Fortune Tech festival in Aspen, Colorado, BuzzFeed CEO Jonah Peretti explained that the deleted posts were published when the site operated as a lab for studying viral content. The articles flagged for deletion, Peretti said, were “trolly,” “sloppily sourced,” or “not something we would ever do today.”

But on Twitter, editor-in-chief Ben Smith said that the deleted posts were “corrected” after Gawker pointed out, in 2012, that they insufficiently credited other websites. (He didn’t explain why “corrected” posts would later on disappear, and BuzzFeed declined to elaborate on the record about specific standards.) Peretti, meanwhile, compared the deleted content to “screen tests,” which reflected the site’s origins as a new media laboratory. Any real reporting, he insisted, remains untouched:

This is largely true. Besides the heavily aggregated listicles we noted on Monday, BuzzFeed editors also targeted short one-off items, like this October 2011 post by senior reporter Mike Hayes, which simply copied and pasted a cool image that other sites were passing around. The creator of that image, Travis Greenwood, told Gawker that Hayes’ post “was still live as of about 8 weeks ago—I use it in my résumé when applying for certain jobs—but was pulled down without any explanation.” (Greenwood’s account supports the theory that BuzzFeed was trying to comply with copyright law, which has given the site trouble in the past.)

Still, the site left at least one notorious listicle unscathed. Last year, The Atlantic Wire reported that the entries in a viral post titled “The 30 Happiest Facts of All Time” were cribbed almost entirely from a recent Reddit thread, in most cases down to the specific wording. Unlike the listicles that got the ax, “Happiest Facts” was published in March 2013—well after BuzzFeed began calling itself a real news organization. Also unlike the deleted listicles: “Happiest Facts” racked up nearly 6 million page views.

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