This isn't ambiguous or in any way contentious. Panda, named after a Google employee but also known as the farmer update, was explictly "designed to reduce rankings for low-quality sites—sites which are low-value add for users, copy content from other websites or sites that are just not very useful", and while the Panda announcement itself was reluctant to use the term "content farm" an earlier blog post by Matt Cutts, Principal Engineer and co-signatory of the Panda announcement, stated that Google was targeting "“content farms,” which are sites with shallow or low-quality content".
So when Demand Media's Richard Rosenblatt recently told Kara Swisher that "I don’t think anyone has defined what a content farm is and I am not sure what it means either"...that was a very strange claim.
Still, I guess the guy's busy, what with arguing about precisely how much traffic an update designed to take down content farms has cost his business (which, remember, is nothing of the sort). So just for clarity here's some tips as to what a content farm is.
Wikipedia is the first hit for "content farm" on Google and provides a workable definition:
"the term content farm is used to describe a company that employs large numbers of often freelance writers to generate large amounts of textual content which is specifically designed to satisfy algorithms for maximal retrieval by automated search engines. Their main goal is to generate advertising revenue through attracting reader page views as first exposed in the context of social spam."
That would do as a defintion of "content farm" (and, by no coincidence at all, of Demand Media). Jay Rosen has another, penned this morning in response to Demand's own confusion:
"Content farm, definition: When the production of crap cannot tarnish the brand because mistrust in the product doesn't impair profitability."
For the purposes of running a content business that depends on search traffic, though, only one definition really matters - and that's Google's. Here it is again:
"Sites with shallow or low-quality content."
And just to clear up one final misapprehension (Rosenblatt again, to Swisher): "We obviously don’t think we are a content farm and I am not sure we can counter every impact if some people think we are." Here's how to tell whether Google, at least, thinks you're a content farm. After Panda, is your search traffic up or down?