This one stat is the whole reason Facebook says it's getting into native content

This week, Facebook announced details of its highly-anticipated Instant news service along with launch partners that include BuzzFeed and The New York Times.

Facebook is asking publishers to write and post articles directly on the social network rather than their own sites. In return, Facebook's algorithm will favor their stories. Additionally, publishers will be allowed to count Facebook article traffic toward their ComScore numbers. The revenue split is generous: publishers can keep 100% of the money if they sell a Facebook Instant advertising campaign and 70% if Facebook sells it.

Why is Facebook suddenly so focused on hosting news articles?

A lot of publishers believe it's because Facebook is greedy. They think Facebook wants to steal their advertising dollars and make them start paying for the free traffic referral love they've been shown over the past year. Entire businesses have been built on Facebook's firehose of traffic, including Distractify, ViralNova and UpWorthy. Facebook could make many of those websites disappear overnight with just a few changes to its algorithm.

But publishers traditionally don't have massive marketing budgets the way major corporations like Proctor & Gamble do. So if Facebook was feeling greedy, media companies be a pretty small group to go after.

Instead, Facebook has hailed one stat as the reason it's launching Instant articles. You can find it in the second paragraph of Facebook's Instant announcement from Monday:

"As more people get their news on mobile devices, we want to make the experience faster and richer on Facebook. People share a lot of articles on Facebook, particularly on our mobile app. To date, however, these stories take an average of eight seconds to load, by far the slowest single content type on Facebook."

Eight seconds is a long lag time. By hosting content, Facebook thinks it can speed up load times and create a better user experience. Facebook offers a much better mobile browsing experience than many publishers do.

Other big tech companies are putting an emphasis on improving mobile viewing experiences too. Google recently announced a change in its SEO algorithm which the press dubbed "mobilegeddon." The change would allow Google to favor mobile-friendly websites in search rankings.

A person familiar with Facebook's thinking told Business Insider that the decision to launch Instant was "100%" dictated by mobile trends. About 60% of online traffic now comes from mobile devices instead of desktop computers. But a lot of online properties haven't adjusted their user experiences accordingly.

"Mobile [news consumption] is a terrible experience, and the mobile web is a wreck," this person said.

Facebook's Chief Product Officer Chris Cox echoed the same sentiment in Monday's statement. "Fundamentally, this is a tool that enables publishers to provide a better experience for their readers on Facebook," he said,