You can see all the thread topics on the main page. To view the actual posts, you have to click on a thread. I think most message boards work like this. Also, you may be sent emails updating you on new posts. You can adjust the frequency of these emails, or turn them off altogether, by going into Settings (the gear icon on the upper right).
I would suggest that everyone go into Settings and personalize their experience, since the defaults may not be to your liking.