With GTDInbox you can easily apply the Getting Things Done philosophy to your Gmail inbox.
As you may already know, Getthing Things Done is a popular productivity method that helps you deal with all your pending tasks in a more organized, efficient way. What GTDInbox does is create as many Gmail labels as needed to identify the different types of actions you can have in this popular method. Then, all you have o do is categorize your incoming messages accordingly.
There's nothing GTDInbox does that couldn't be done by yourself, but this neat extension saves you the pain of having to do all the work manually. GTDInbox also adds a special box on the left side pane that gives you access to lists of projects, references and other elements.
GTDInbox includes a complete settings menu with which you can customize the extension's behavior to fit your needs. Do take into account that it's still in development, which means you could encounter the odd bug now and then.
If you have a Gmail account and would like to start using the Getting Things Done productivity method, GTDInbox is the extension you need.