NPR media reporter David Folkenflik writes in his forthcoming book
Murdoch's World that Fox News' public relations staffers used an
elaborate series of dummy accounts to fill the comments sections of
critical blog posts with pro-Fox arguments.

In a chapter focusing on how Fox utilized its notoriously ruthless
public relations department in the mid-to-late 00's, Folkenflik reports
that Fox's PR staffers would "post pro-Fox rants" in the comments
sections of "negative and even neutral" blog posts written about the
network. According to Folkenflik, the staffers used various tactics to
cover their tracks, including setting up wireless broadband connections
that "could not be traced back" to the network.

A former staffer told Folkenflik that they had personally used "one
hundred" fake accounts to plant Fox-friendly commentary:

On the blogs, the fight was particularly fierce. Fox PR staffers
were expected to counter not just negative and even neutral blog
postings but the anti-Fox comments beneath them. One former staffer
recalled using twenty different aliases to post pro-Fox rants. Another
had one hundred. Several employees had to acquire a cell phone thumb
drive to provide a wireless broadband connection that could not be
traced back to a Fox News or News Corp account. Another used an AOL
dial-up connection, even in the age of widespread broadband access, on
the rationale it would be harder to pinpoint its origins. Old laptops
were distributed for these cyber operations. Even blogs with minor
followings were reviewed to ensure no claim went unchecked. [Murdoch's
World, pg. 67]

In the book's endnotes, Folkenflik explains that "four former Fox News
employees told me of these practices." It's unclear whether these
tactics are ongoing.
http://tinyurl.com/mzljlr4

What a surprise.