People and organizations are doing a lot of interesting things with Mozilla technologies. Here are two of the many Mozilla-based applications available. If you would like to suggest other applications to feature, please leave a comment.
BlueGriffon is a next-generation WYSIWYG editor for the web based on the Composer tool from the original Mozilla Application Suite that helps you create standards compliant HTML and CSS code.
Sogo is a groupware server with a focus on scalability and open standards that lets you share your calendars, address books and mails with a completely free and open source solution.