1. Automatic save frequent searches. Search history.
2. Provide related messages as context when viewing an email, like previous messages in the same thread, messages from the same group of authors, and messages with similar content. However, reading some emails like advertisement and newsletter don’t need context. This idea, in general, is organizing emails by similarity of contents rather than by time or threads. This organization probably is more close to the representation of concepts, lexicons, events and other things. Therefore, people will find it more natural to work with email client program in this way.
3. To achieve the above goal, a topic classifier is needed to index all the messages in Inbox, Sent and etc.