Chat by thunderbird.

Hi!
Certainly that you see that amzing option(if you use gmail and her web client). of grouping your email's by chat's.
With this tutoria you can give you an solution.
But first some images.

 In this case you see gmail using this option.

In the second case you see thunderbird after I run this tutorial.
.
In 1ºst place you need to click in Menu bar. Now click in "View", point to "Topics" and click in option "unread".
Enjoy.