An expired contract is behind the apparent absence of all new Associated Press content from Google News, throwing search engine optimization (SEO) for news media websites into disarray.

Search Engine Land’s Danny Sullivan reports that Google has confirmed that it has not posted any new AP content to Google News since December 24, and speculates that this absence is related to the ongoing negotiations between Google and the AP over the licensing agreement that expires "near the end of this month."

Sullivan also links the content dispute between Google and the AP with a similar spat between the search giant and Rupert Murdoch, the owner of News Corp and a vociferous critic of the ad-supported model of online newsgathering. Murdoch has repeatedly threatened to de-list his content from Google’s results and implement a for-pay system in its place.

However, search engine optimization (SEO) experts have said that Murdoch runs a terrible risk in switching to such a system, warning that News Corp could stand to lose a fortune in advertising revenue through a large-scale diminution of its user base.