If you are on Facebook today, you might see something different on your news feed. Now your friends’ posts will sometimes be grouped together based on the subject matter of those posts.

For instance, you might see a post that says “John Carter and 2 other friends posted about The Dark Knight.” All of the people mentioned as well as the topic will all link to their respective pages. The topic will be linked even if the original posts did not tag the actual pages.

Facebook announced this just a little while ago as part of a photo uploaded to their Facebook page (yes, Facebook’s Facebook page). Here’s what it looks like –

Note that Dmitry and Abhinai didn’t tag the actual Harry Potter page in their posts. But when Facebook groups the stories together by topic, they tag the page.

Not only will your friend’s posts about certain topics come bundled together, but so will posts by pages. For instance, Facebook grouped together three posts by Search Engine Land, Read Write Web and Mashable, all of which concerned Google.

Here’s what Facebook says about the change:

You may notice some of your News Feed stories are now grouped together by topic. We want to show you the most relevant and interesting information, and this test is designed to show you trends among what your friends are saying.

So – Facebook’s version of trending topics? Of course it’s not the same as trending topics on Twitter that concern large volumes of related content – global trends, and trends by country or city. It could serve as a more intimate way to utilize trending topics.

The other side to this brand new feed item is obviously the benefit to pages. Even if the original posters choose not to directly tag a page, this story aggregation will link to specific pages. Each time one of these “X and X posted about X” stories appears on a news feed, it’s a social advertisement.

There could be some hiccups to the new item, however. Facebook Google+Reader”>confirmed to Josh Constine that “its natural language processing doesn’t detect sentiment, how a Page’s name is being used, or whether the mentioned Page was actually the focus of the update. As such, the Posted About stories may highlight Pages that aren’t actually what a user was discussing, or that are being talked about negatively.”

That means that you might see a post that informs you about 4 friends posting about Harry Potter, but only one would be positive or relevant. You could have 3 “Harry Potter Sucks” posts and one irrelevant post like “My golf game is so magical I feel like Harry Potter out there.”

Still, this is an interesting new feature for brands and could allow Facebook to feel more immediate and connected. Trending topics seems to be something that people like across all social media platforms.