The below screenshots show a new module in Facebook newsfeed: "Trending Articles". It is a clustering of popular posts based on Open Graph actions of similar types (in this case "read" articles). The clustering by type is itself interesting (as it has implications for Open Graph and applications) - but the presentation is especially unique as we have not seen modules like this appear within the newsfeed. The clustering and the in-line scrolling are entirely new formats. If popular, it represents possibilities for other formats like photos, check-ins, etc.
It is also interesting that you cannot comment from within the module. Users can share - but not comment. This is bizarre because it differs from what appears in the Ticker. It also is potentially harmful for an article's overall visibility in the Facebook feed / ecosystem.