Recently Google penalized Interflora, a very popular UK flower seller, for using advertorials as a way to boost their site's ranking before Valentine's Day. Then we noticed that Google not only penalized Interflora but also the news sites that were placing the advertorials on their behalf by downgrading their PageRank to zero.
Google Team Say, "Please be wary if someone approaches you and wants to pay you for links or "advertorial" pages on your site that pass PageRank. Selling links (or entire advertorial pages with embedded links) that pass PageRank violates our quality guidelines, and Google does take action on such violations. The consequences for a linkselling site start with losing trust in Google's search results, as well as reduction of the site's visible PageRank in the Google Toolbar. The consequences can also include lower rankings for that site in Google's search results.