Regular readers of Gawker may have noticed that for much of the last four days the most popular story, according to the sidebar, is a post from February 2010 called "This is What Getting Your Vagina Vajazzled Looks Like."

The post, by then-weekend editor Foster Kamer, now a writer and editor for Complex, is a brief, two-paragraph item in which is embedded a video of a young woman having her pubic bone professionally decorated. There is a link out to a Buzzfeed "community post" by a brand (a publication?) called "The Luxury Spot," the source of the video.

Over the last four days the post has amassed nearly a million new page views. Where is it all coming from?! Facebook, of course:

(Table courtesy Gawker growth associate Jessica Smith.)

I mean, it's all Facebook. Compare the seven-day Chartbeat graph for "The Reality of Dating White Women When You're Black," a good-sized hit for us from Tuesday, with that of the vajazzling post. Purple is social—mostly Facebook; blue is links from external sites; yellow is links from Gawker.com. Notably, relatively little of the traffic—maybe around 15 percent—is coming from the sidebar links on Gawker or other Gawker Media sites.

And compare those curves, too! Regular, diversified traffic on a decent hit is a quick burst immediately after publication, tapering off throughout the day, a smaller peak for the next day, another valley and on until it flatlines. It hits its peaks around midday and early afternoon, when office workers are at the computers.

Facebook traffic, on the other hand, is a steady rise that doesn't peak until around 10 p.m. eastern time (and drops off immediately). Weirder still, it gets bigger: Wednesday night, the post was receiving around 7,000 hits an hour at its peak; Thursday, it was hitting 8,000.

There may be a Facebook "patient zero"—a widely seen or argued-over post that re-ignited interest on the social network site—but if there is we haven't found it. And accounting for an individual post's success on Facebook is a bit like explaining why one lottery number is a winner and another is not. But if you believe there is a science to social virality, Kamer's post is well-positioned. It has a video, which means users will spend more time on the page (Facebook, we think, rewards time spent on outgoing links and punishes sites and articles that are quickly dismissed). It's sexy, and about sex, but not pornographic, or entirely not safe for work—people will feel comfortable sharing it on their public Facebook pages. And, finally and maybe crucially, it's documentation of a phenomenon about which people have strong opinions, opinions they are no doubt inclined to share.

But there are a lot of posts on this site like that. Why this one? ¯\(°_o)/¯

(Vajazzling, for those who lack comprehensive knowledge of recession-era trends in personal grooming, "involves getting a Brazilian bikini wax and then putting individual Swarovski crystals on the outside [...] of the vaginal region using adhesive," as Gawker's own Doree Shafrir wrote two days before Kamer. Shafrir, who linked to but did not embed the same video in her post, is now Buzzfeed's executive editor.)