In the official Google News blog a about commerce and promotional journalism has came recently. This reminder says that the sites which involved in the service shouldn't put in their materials links and other ads. Any form of promotional tactics, such us selling or monetizing links within articles is recognized by the Google News service like violation of its quality guidelines. Google's representatives have warned publishers: if only advertising links are seen in some materials, the entire content of the website will be remove from the service.
Let us remind, that about a month ago Google released a similar warning to all webmasters. This warning contains reminder about penalties that will be applied to sites which selling links. February's post was published just after British site Interflora, the country's largest flower shop, had been exclude from the SERPs. On the eve of Valentine's Interflora purchased a large number of links from news sites. After that the site and its donors suffered (Google reduced to zero PageRank of about 50 news sites) .
The leading webmasters suggest that today's post is also associated with the imposition of the ban on any large site. Maybe we will know about it more in the near future.
The rule that members of Google News shouldn't use the service to promote or advertise any products/services aren't new. It always has been present in the manual for this service: "We need only news! News Google is not an advertising service. Users are not very interested in sites which created mostly to promote some product or organization".