When there is a lot of activity on your page, you can structure your posts with labels.
Add labels to your posts by typing them in the designated bar while creating a post. In case a certain label already exists, it will pop up as you type. If not, create the label by typing it and selecting Create new label. You can add as many labels as you like. Adding labels to your post will make it easier to search in the item stream for similar posts (such as 'Assignments' or 'Lecture slides').