There are three main ways to see what is new in the community.
The Piazza - the piazza lists all new public and group posts (of the groups you are a member of) in a reverse chronological order (i.e. the newest one is at the top). If a post is commented on it goes to the top and so on.
New Activity - the new activity page shows you all posts that you have checked yet (i.e. you clicked to read them) or posts that you have read but have new comments. If that page is empty it means you are fully updated on everything!
My Activity - the "My Activity" page lists content that you have either created yourself or participated in by commenting on something someone else said.
Finally you can also see new Group Content by clicking on "My Unread Group Posts" from under your username menu on the right-hand side.
