Here you specify whether you want to be notified about new chat messages in addition to missed call and voicemail notifications. You will be informed even if the app is running in the background. You can define how the messages should be signaled within the iPhone settings under Settings | Notifications | Enreach Contact.

Here you can set whether you want to be informed when things change around the chat room. E.g. if the room name or the topic has been changed or if someone has entered or left the room, etc.