Roundcube Webmail is a browser-based, multilingual IMAP client with an application-like user interface. It provides the full functionality you expect from an email client, including MIME support, address book, and folder manipulation. High extensibility is granted by the plugin API and the user interface is fully skinnable using XHTML and CSS 2.
Noosfero is a Web platform for social networks. Besides the regular social network features (such as friends and communities), Noosfero offers a full-featured CMS, making every user or community profile a complete Web site with several types of content (including text, image gallery, and file uploads), RSS feeds, agenda, the possibility to set custom themes, and other features. It is also possible to run several independent social networks within the same Noosfero installation.