Some features, and access to free courses, are constrained by point levels. The way to help others move up in the point standing (see the Leaderboards in the menu above) is to like their posts and comments, and the way to move up yourself is to post and comment so others can like them. Level 2, for example, requires just 5 points. Each like you receive gives you 1 point.
Participation β Engagement β Growth.