Updated with comment from Facebook.

Facebook may be experiencing some technical difficulty. According to several sources, a key part of Facebook’s recently launched Open Graph, which connects users’ data to third-party websites, appears to have been down for more than 13 hours. Facebook has yet to respond to a query about the current status of its Graph API and whether it’s up and running again.

Several real-time online search services that pull content from Facebook, such as Booshaka and OneRiot.com, appear to have stopped receiving fresh content. A search at Booshaka for “stock market” clearly shows the last content being aggregated 13 hours ago.  OneRiot.com is currently only aggregating content from other social-media sources, such as Twitter or Digg. Openfacebooksearch.com also shows stail data.

There are two concerns here: Facebook’s responsiveness, and Facebook’s communications with advertisers and publishers who may come to rely on its data. As Facebook pushes into the open Web and offers its API to businesses, a quick fix on an API could be considered imperative. In its early years, Twitter suffered from outages to the point that its “fail whale” image displayed when the site was down became a pop-culture icon.

The stability of Facebook’s technical infrastructure could become another debating point in the argument over whether Facebook deserves to own the Web. Privacy and security remain big issues for Facebook with calls for action from consumer groups, privacy advocates and members of Congress on the rise.

Update: The outage seems limited to the search function within Facebook’s Graph API.

A Facebook spokesperson responded:

Our engineering team is investigating questions about specific search functionality of the API, but we can confirm that search and other aspects of the Graph API did not go down. It appears that indexing of new stream content has been delayed for the past 12 hours, but this is being rectified currently.

Update (12:00 PST): Facebook has notified us that the indexing problem has been fixed.