Google has introduced a new feature today, to combat email overload.
Priority inbox is a beta feature that splits your inbox into three sections: “Important and unread,” “Starred” and “Everything else”. The system enables Gmail to automatically flag messages as important. Gmail uses a variety of signals to predict which messages are important, including the people you email most and which messages you open and reply to. As you continue to use Gmail it will get better at categorizing messages for you.
If you think this feature seems familiar then you're not wrong. Hotmail recently introduced a similar feature which allows you to "sweep" your inbox clear of clutter. Although Microsoft's implementation is less automated, it's also trying to solve inbox clutter.
Priority Inbox will be rolling out to all Gmail users, including those who use Google Apps, over the next week. Once you see the "New! Priority Inbox" link in the top right corner of your Gmail account then you're all set.