Notifications will alert you whenever someone has "hearted" or commented on your Whispers, or sent you a new Chat. If you have a notification, your notification bell should appear on the bottom toolbar:
Once you open your Notifications or Activity, you can view the updates on your Whispers or in your Chat Inbox.
To turn off all notifications be sure that you have the settings turned off both in the Whisper settings and in the Application Manager of your phone's Settings.
Click here for more information on: hearts and replying to Whispers.