If students are allowed to reply to announcements, you can also allow students to like replies in an announcement. If an announcement allows liking, users will see a Like icon within each announcement reply. By default, liking is available to all users in the course; however, you can choose to restrict the option to graders only.
The Like icon is enabled on a per-assignment basis.
You can also like announcement replies as an instructor.
Set Liking Options
You can also select two additional options when allowing announcement likes.
Only graders can like : select this checkbox if you want to limit the liking functionality to only graders in the course, which means only users with the Edit Grades permission can see the Like link. However, all users will still see the total number of likes for each reply.
Sort by likes : select this checkbox if you want the announcement to sort replies by the number of likes. Sorting cannot be changed by any users unless you remove the sorting setting. This option may take at least 10 seconds to cache the page and view sorting appropriately.
Announcement replies are sorted in descending order.