Simple Mail 2.82

Simple Mail is a mail notifier & client (POP3/IMAP/SMTP) for Firefox. With Simple Mail you can get notified, read and write email messages inside Firefox.

Simple Mail will mark with red the important messages.

Usage:
Configure one or more accounts in Preferences, set account refresh time and get notified of new mail. When new mail arrives, Simple Mail shows new messages count in status bar. You can click Simple Mail icon to open received messages in a separate browser tab. Also Simple Mail has a toolbar button, which you can put on toolbar to access SM easily.

Filters:
Use filters to automatically dispose incoming messages. Each filter consists of a set of rules and a set of actions. Rules are matched against incoming message properties and on success actions are executed. You can use filters to:

The Simple Mail add-on is cross-platform and it works on Mac OS X, Windows and Linux.

Here are some key features of "Simple Mail":
Ссылка: http://releases..b/mozilla.org/addons/5593/simple_mail-2.82-fx.xpi