I've paid attention to criticisms of the Huffington Post over the years and made one or two of my own, but I've never really thought about or investigated Huffington* or the site in any great depth. The S.H.A.M.E. Project's latest is an indictment of Huffington, reaching deep into her past politics and connections. I haven't confirmed all of the information, of course, and a portion might well not hold up under scrutiny, though some of even the most damning claims are verifiable simply by clicking the links to HuffPo itself.
Some key quotes:
Huffington Post markets itself as a progressive publication, but publishes corporate propagandists, government flacks, lobbyists for dictators, bankers, cult leaders, self-help hucksters and medical quacks peddling false and sometimes dangerous medical advice, right alongside HuffPo's real reporting. Greg Coleman, Huffington Post president and chief revenue officer, bragged that the company's "sponsored content" strategy—which deliberately obscures the line between journalism and PR—had helped his company "more than double" its advertising revenue in 2010, saying "the level of interest we have in this marketing form is gigantic . . ." The Guardian called HuffPo the "grand master" of blurring "the line between advertising and editorial … via sponsoring schemes."
Some in the medical community have condemned the Huffington Post for publishing dangerous medical quackery. In 2009, a physician published an article in Salon criticizing HuffPo's promotion of "bogus treatments and crackpot medical theories," including curing the Swine Flu with deep cleaning enemas, fraudulent spiritual healing techniques and risky cancer treatments. Science writer and Vanity Fair contributing editor Seth Mnookin wrote: "For whatever reason, HuffPo seemed to have a particular bee in its bonnet about vaccines and autism: If you made a list of the most irresponsible, misinformed people on the topic, it was a safe bet the majority of them had been given space for their rantings on the site." Many of these authors use Huffington Post to promote their books and services. [links to sources in the original]
*I did read her Picasso biography back when I was I think still a teenager. Don't remember caring for it particularly. I see now that there were accusations of plagiarism.