For Live chat (public chat area), click the link at the very top of the page called Live Chat, choose a room from the "select" drop down menu. Once in a room, if you look to your right, you will your name listed as being in that chat room. If you see any other names listed with yours, then they are in the room too. Many are meeting friends at set times in a chat room; this may be something you want to try. If you are a member of a group, you can get your group together at a specific time too! Use the Shoutbox you see on this page over to your right to ask others to go to chat rooms too! Hope this answers your questions about chat and messenger and clarifies their use!
Note: If you see typed text from conversation, but do not see others in the room, it just means they were there and you are seeing what was typed during the day. It refreshes each day. Also, if you type to someone who appears to be in the room with you, but they do not answer, they may have walked away from their computer or may be on another web page at the time.