Fox News
The folks at Fox News are a little miffed about being left off Facebook's list of the 40 "most-shared articles" of 2011. An unbylined story on accuses "the world's largest social network" of "acting unsocially" because its list is dominated by The New York Times, CNN, Yahoo and The Huffington Post. Fox claims it had at least a couple stories (including how to deal with a potential zombie apocalypse) with more Facebook shares than others on the list, but says Facebook is using a "a mystery metric the company refused to share, leaving many news agencies friendless."

Update: Facebook spokeswoman Malorie Lucich sent us a response explaining how the articles were ranked:

We included all news organizations, including Fox News, in our search, and looked for the articles with the most shares, likes and referral traffic (after the articles were shared, which were clicked the most by friends). To ensure we found the most shared articles, we took a comprehensive look at all the ways an article could have been shared (this included clicking the Like button, clicking the Share button, copying and pasting a link to a news article and posting it to the profile, and sharing a share on Facebook by clicking "Share" beneath an article after a friend posted).