Chrome/Firefox: Gmail labels can be useful for managing your inbox and getting things done, but if you'd like more organisation than they can offer, ActiveInbox helps you organise them like tasks so you can more effectively manage what you need to do.
We've mentioned ActiveInbox a few times before, back when it was called GTDInbox, but it has come a long way over the years. Now, instead of just using your labels to tell you when you need to act on an email, it can also split up your messages into projects, show you previous emails related to a given task, and see other contacts participating on that project with you.
Of course, nothing's better than seeing it in action, so check out AciveInbox's video demo above to see everything it can do. If you like how it works, you can download the free extension for either Firefox or Chrome.