The subject of the moment is content. High-quality content. Shareable content. Authentic content.

There is much hand-wringing and discussion around what constitutes good content, how it can be effectively distributed through social media, and whether shareable (or, gulp, “viral”) content and thoughtful, informative content are mutually exclusive.

Given some recent news and developments in this content discussion, I wanted to inquire: how do social networks like Facebook and au courant publishers like BuzzFeed or Upworthy define good content? And what is it about good content that makes it so successful at gaining distribution through social media sharing?

In an interview published today in All Things D, Facebook’s News Feed product manager, Lars Backstrom, located the source of high quality content in the concept of “user value”. Recent tweaks to the News Feed’s algorithm (often called EdgeRank) are designed, Backstrom says, to increase the prevalence of content that provides value to Facebook users.

So, good content is content that provides value, Facebook says. And Facebook, with EdgeRank, is the arbiter of what kind of content is valuable enough to be put in front of its users on the News Feed.

But how does Facebook define “value” when it runs content through its algorithm? Backstrom doesn’t explicitly say, backpedalling instead to state “we’re not trying to impose our will and view on the world … we’re trying align our definition of value with that of our users.”

In its initial communication about changes to the News Feed algorithm, Facebook indicated that user surveys revealed that “people prefer links to high quality articles about current events, their favorite sports team or shared interests” over “meme photos”. But in his interview, Backstrom walks back this implied threat to LOLcat-like memes: “it’s not like you’re never going to see a funny cat photo from Imgur or some photo-sharing site anymore. It’s that maybe you’ll see 10 percent less of that, and 10 percent more [news] articles.”

To restate, then, Facebook defines good content as content that provides value to users according to each user’s own definition of value (as long as it can be algorithmically determined).

For BuzzFeed’s co-founder and CEO Jonah Peretti, good content is defined primarily by what people share. In an interview at the American Magazine Media Conference back in October, excerpts of which were published yesterday in Fortune, Peretti explains that BuzzFeed is a new kind of media company. It is a media company “focused on making content for the social web, with sharing being [its] distribution.”

Peretti has great ambitions for BuzzFeed and its strategy of shareable content distributed through social media. In a widely-cited internal memo that was posted to LinkedIn in September, Peretti wrote: “We have the potential to be a defining company, the same role the traditional media companies played decades ago.”

The type of content that BuzzFeed has become known for is not what some might necessarily considered ‘high-quality’ or ‘valuable’ (the top performing post of the last week is a list of animated GIFs entitled ‘26 Problems Only Anxious People Will Understand’), but it is driven by an intense focus and understanding on human psychology and motivation.

Peretti, who also co-founded the hugely successful website The Huffington Post, will often tell audiences that he has spent a lot of time thinking about what makes people share, and this informs his approach to content on BuzzFeed (this article in New York magazine offers a detailed profile of Peretti’s background).

Creating content that connects to a shared sense of identity is a key plank of BuzzFeed’s strategy — whether that means a place identity (‘29 Things Only People From The Midwest Understand’) an identity based on credentials (‘27 Ways Going To USC Changed Your Life’) or an identity of self (such as the post on anxiety referenced above). This kind of content taps into the reader’s sense of self and encourages them to share the post with others in the same identity group.

So, good content to BuzzFeed is content that people love to share, often because it touches on an expression of a shared identity.

The success of BuzzFeed has spawned a number of other sites with similar strategies for distribution via social media sharing. One that has rapidly emerged on the scene is Upworthy, a content sharing site that describes itself as “a social media outfit with a mission: to help people find important content that is as fun to share as a FAIL video of some idiot surfing off his roof.”

In contrast to BuzzFeed’s general focus on entertainment and pop culture for its most-shared material, Upworthy claims as its territory shareable content that is meaningful, rather than self-indulgent, voyeuristic or ironic. Similar to how BuzzFeed taps into a constellation of shared identities to encourage social media sharing, Upworthy’s thematic focus on meaningful and uplifting (or even challenging) content relies on its audience’s desire to be the kind of person who believes that the better angels of our nature will prevail over selfishness, cynicism and snark. It has also perhaps proven itself to be the epitome of smarm.

Upworthy’s content is known for its highly engaging article headlines, which are designed to exploit a so-called “curiosity gap” in users who encounter their content on social streams, compelling them to click through (and ideally, re-share). This strategy has been widely criticized and parodied, and yet has nonetheless proven to be extremely successful.

Good content, according to Upworthy, is irresistible, meaningful and positive content that people love to share.