Microsoft Outlook is a personal information manager available as a part of the Microsoft Office suite. The current version is Microsoft Outlook 2010 for Windows and Microsoft Outlook 2011 for Mac.
Although often used mainly as an email application, it also includes a calendar, task manager, contact manager, note taking, a journal and web browsing.
It can be used as a stand-alone application, or can work with Microsoft Exchange Server and Microsoft SharePoint Server for multiple users in an organization, such as shared mailboxes and calendars, Exchange public folders, SharePoint lists and meeting schedules. There are third-party add-on applications that integrate Outlook with devices such as BlackBerry mobile phones and with other software like Office & Skype internet communication.
However, being popular doesn’t mean it is the best. There are several open source alternative email clients that have the same, or even better functionality than Outlook. Let’s take a look.
1) Mozilla Thunderbird
Mozilla Thunderbird is a free, open source, cross-platform email and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser.
Thunderbird has a wide list of features of which some are: support for POP and IMAP, built-in RSS support and spell checking. Thunderbird also has an integrated usenet news reader. More advanced features of Thunderbird include: Junk mail (spam) filtering and protection from phishing.
It has a very customizable user interface and its functionality can be extended wth the help of addons. Lightning is one of such addons that adds calendar and scheduling functionality to the Mozilla Thunderbird.
The latest version of Mozilla Thunderbird is 45.1.0.
Evolution or Novell Evolution is the official personal information manager and workgroup information management tool for GNOME. It combines e-mail, calendar, address book, and task list management functions. It has been an official part of GNOME since version 2.8 in September 2004. Evolution development is sponsored primarily by Novell.
Its user interface and functionality are similar to Microsoft Outlook. Features include iCalendar support, full-text indexing of all incoming mail, powerful email filters writable in Scheme, and a “Search Folders” feature.
Evolution can be connected to Microsoft Exchange Server (by evolution-mapi plugin) or to older versions than Exchange 2007 using their web interfaces and an Evolution add-on formerly called Ximian Connector. OpenSync enables it to be synchronized with mobile phones and other PDAs.
Licensed under the terms of the GNU General Public License, Evolution is free software.
The latest version of Evolution is 3.20.2.
3) Claws Mail
Claws Mail is a lightweight (GTK+ based) free and open source email and news client. It offers easy configuration and an abundance of features. It stores mail in the MH mailbox format and also the Mbox mailbox format via a plugin. Claws Mail runs on both Windows and Unix-like systems such as Linux, BSD, Solaris, and Mac OS X.
Formerly known as Sylpheed-Claws, it started in April 2001 as the development version of Sylpheed, where new features could be tested and debugged, but evolved enough to now be a completely separate program. It forked completely from Sylpheed in August 2005.
Claws Mail provides many features,among them are – search and filtering, security (GPG, SSL, anti-phishing), import/export from standard formats, external editor, templates, customisable toolbars, themes support and more. Its functionality can be further extended with the help of plugins.
The latest version of Claws Mail is 3.13.2.
4) Mozilla SeaMonkey
SeaMonkey consists of a web browser (SeaMonkey Navigator), an e-mail and news client program (SeaMonkey Mail & Newsgroups), an HTML editor (SeaMonkey Composer) and an IRC client (ChatZilla).
The development of SeaMonkey is community-driven and is governed by the SeaMonkey Council. It is tri-licensed under Mozilla Public License, GNU General Public License and GNU Lesser General Public License.
Some of SeaMonkey Mail’s features includes support for multiple accounts, junk mail detection, message filters, HTML message support, a dictionary, an address book, customizable labels, add-ons and mail views as well as integration with the rest of suite.
The latest version of SeaMonkey 2.40.
5) Zimbra Desktop (Bonus)
Zimbra Desktop is a free but proprietary email client that allows you to meld the online and offline worlds – storing and synching your email, calendar, contacts, files and documents in the cloud, yet having them locally accessible when on the road.
Zimbra Desktop aggregates information across accounts (Zimbra, Yahoo! Mail, Gmail, Hotmail, etc.) and social networks (Facebook, Digg, Twitter, etc.) to help make communicating & sharing information easier than ever. It also manages your Contacts and has a Calendar, Document editor, Task list and Briefcase for storing all your attachments.
Zimbra Desktop is cross platform and is available for Microsoft Windows, Mac OS X and Linux.
The latest version of Zimbra Desktop is 7.2.7.