In the Conversation view your messages are grouped to make it easier to follow the thread of an email exchange. A conversation thread begins when you send or receive an email and then send or receive subsequent replies and forwards based on the original email. The subject displays only once in your Inbox, and the number of email messages in the conversation is shown.
Conversations containing unread messages are shown in bold with a blue dot to the left of the sender’s name.
Conversations can span folders. For example, one could be in your Inbox, another in your Sent folder, and others in another folder. If you move a conversation from one folder to another, all messages within that conversation are also moved to that folder. Messages in the Sent folder and in the Trash folder are not moved.
To create a new conversation thread, you must create a new message, not reply to or forward an existing message.
Email messages in your mailbox can be organized by the date a message is received and by Conversation.