Editor’s Review: A free mail client for Firefox.

Simple Mail is a free mail client for Firefox.
Statistics show that over 80% people has over one email account, and over 30% people has over 3 email accounts. And we have to sign in multiple email accounts to check, read and write messages. With Simple Mail you can manage all the email accounts easily - it allows you to get notified, read and write messages for multiple email accounts inside Firefox.

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.

Accounts:
Support multiple email accounts and POP3/IMAP/SMTP protocols.

Address Book:
Autocomplete box suggests recipient names/addresses as you start typing them and you also can configure the Groups of contacts.