View Profile This option only show for registered members and will take you to their profile page.
Ignore Ignore option allows you to not see any messages sent by the person you have ignored.
System message This option allows to you see or hide "user entered room" and "user left room" messages.
Block users This is the list of members you have blocked and you can unblock them from here.
Middle of the page shows all the messages exchanged in the room.
Mention Mention allows to mention a member in your message and it will appear highlighted to them.