Facebook has announced two new features for its Comments Box plugin, which lets third party websites embed Facebook comments: Chronological Sort, and Boost Comment.
Comments can now be sorted in three ways: besides the reverse chronological sort option, you can now also have the comments sorted chronologically or by their social ranking, which will take into account likes and comments from other users. To choose an option, click the arrow next to the number of comments in the box.
Furthermore, if a particular comment is especially relevant to you and you want to push it to the top, you can do so by clicking the "Boost Comment" option.