If you've got healthy discussion going in the posts on your class feeds, you may wish to check on the contributions of individual students. Here's a few approaches...
You can click on the chart icon on the left of your class and see an overview of each student's participation. You can select different options and see the results such as Units read, posts participated.
You can click on any of the member of your OLP classroom and see their profile, selecting the "stats" tab shows you an overview of their activity.
The previous statistics provide a pretty blunt measurement of student activity. To get a good grasp on the quality of participation, you can filter the class feed to see participation by individuals. This sorts and highlights the participation by only the selected student allowing you to quickly scan their posts and comments.