There are plenty of open source email clients already on the market, but there's always room for more. Roundcube is a free and open source Web mail application that contains full support for HTML and MIME messages, IMAP folder management, and more.
For a GPL-licensed app that hasn't even reached maturity as a 1.0 release (the current version is Roundcube 0.4 beta), the client already sports a batch of nice features and shows promise for becoming a solid way to manage a landslide of email. Between the address book with LDAP integration and unique privacy features, Roundcube just might have a winner on its hands. Let's take a look at some of its features:
The three-paned message viewing panel supports drag and drop. Window panes can easily be resized to accommodate the smallest and largest of screens.
The multi-lingual message display supports 65 languages.
The integrated TinyMCE editor lets you create messages with images that appear within in the body of the text.
Privacy protection blocks images from appearing in emails from unapproved senders.