Facebook has been granted a patent on the Newsfeed, "displaying a news feed in a social network environment." Nick O'Neill at AllFacebook found the patent first and says it could be "one of the most significant social web patents" in a decade.

If all algorithmic ranking and delivery of social activity updates to social network users falls under this patent Facebook applied for in August 2006 (one month before it launched its controversial Newsfeed) then there's going to be a whole lot of trouble for sites all over the web. We've got calls and emails in with Facebook PR, we're going to start thinking and reading up about what this could mean but for now, please join us over on Google Buzz to discuss this story as it unfolds in real time. Our coverage continues below.

Working Summary: This patent appears to cover primarily implicit user activity updates (such as "person X changed their employer listed or their relationship status or became friends with person Y") and the dynamic ranking of those items when delivered in the context of a social network. In contemporary Facebook terms, it would probably cover the News Feed but not the status messages in the Live Feed. It would probably not impact what Twitter is doing today. It could impact any number of other social networks - like LinkedIn, Ning and other systems not created yet. But it's possible that Facebook will only use this patent defensively. Time will tell what the company's intentions are.

18 months ago we wrote the following, as site after site adopted a Newsfeed model for delivering updates to users:

Today we're ready to declare The Newsfeed the dominant internet metaphor of the day; the cascading waterfall of updates from your friends, with comments swirling even around those - that model is everywhere now!

MySpace, Flickr, Yahoo!, Twitter (?), the sharing part of Google Reader and even Google Buzz - do all of these sites have technology at the center of their social experiences that falls under this new patent of Facebook's? Twitter probably doesn't fall under this patent because the filing

Text of the Patent

Here's the abstract for the patent, filed August 11th, 2006, Mark Zuckerberg listed as the first inventor:

A method for displaying a news feed in a social network environment is described. The method includes generating news items regarding activities associated with a user of a social network environment and attaching an informational link associated with at least one of the activities, to at least one of the news items, as well as limiting access to the news items to a predetermined set of viewers and assigning an order to the news items. The method further may further include displaying the news items in the assigned order to at least one viewing user of the predetermined set of viewers and dynamically limiting the number of news items displayed.

An initial response from Google's Chris Messina, a leader of the Activity Streams standards organization that includes Facebook.

I hope that this is defensive and Facebook doesn't intent to enforce this patent. this is why the Open Web Foundation was instantiated, so we could work on these kinds of features without any one organization invoking patent rights. this is just one more example of how the patent system isn't architected to support the right kind of innovation.

[For all the other websites using activity streams-like formats] if this patent gets enforced, you could do it in reverse chronological order where there is no algorithmic ranking or you could license this technology from Facebook. i don't know what this means for Facebook's Platform and Connect.

It sounds crazy, but did Facebook invent the algorithm-driven newsfeed? Messina wasn't quite willing to grant that in our conversation, but it's a tough call. "Facebook certainly built the whole phenomena around the newsfeed," he said.

Don't miss: Dave Winer's take on this news.

Nick O'Neill has published the following update to his story, but I'm not buying his conclusion:

It appears that this patent surrounds implicit actions. This means status updates, which is what Twitter is based on, are not part of this patent. Instead, this is about stories about the actions of a user's friends. While still significant, the implications for competing social networks may be less substantial.

Implicit actions are a very big deal. LinkedIn contacts making new connections or changing their jobs would be the most immediate example that comes to mind. If offering a stream of updates of the non-status messages of friends is something Facebook alone could deliver, that would be a major loss for the rest of the social web.

There's an active conversation going on our Google Buzz page for this topic, too.