Google has a new Gmail tool to help users manage their inboxes. "Priority Inbox" splits the inbox into three categories: important messages, starred messages, and the rest. Priority Inbox's utility lies in the algorithms that determine which messages to automatically flag as "important" to you—it looks at which people you regularly respond to and which emails you delete, archive, or star. Those emails get pushed to the top. You can help train Priority Inbox by flagging messages as important. More details at ReadWriteWeb, or see the video in the gallery.