PHP On Pie is a PHP framework that combines the best ideas from PHP projects like Drupal, CodeIgniter, Kohana, and ZendFramework. It has very few core concepts: classes, models, events, slots, and tools. It lets you repackage completed apps into plugins that you or others can use later. Its smart database classes allow you to implement vertical and horizontal partitioning (sharding) easily to handle millions of users.
SOGo is a very fast and scalable modern collaboration suite (or groupware). It offers calendaring, address book management, and a full-featured Webmail client along with resource sharing and permission handling. It also makes use of documented standards (IMAP, CalDAV, CardDAV, etc.) and thereby provides native connectivity (without plugins) to many clients such as Microsoft Outlook, Apple iCal, the iPhone, Mozilla Lightning, and a plethora of mobile devices via SyncML. It can reuse any existing email and database infrastructure, avoiding long hours of site restructuring.
ZEG, which stands for "Zero Effort Groupware", is a virtual appliance of SOGo intended to provide a complete out-of-the-box testing environment. SOGo is a collaboration suite (or groupware) with speed and scalability in mind. It offers calendaring, address book management, and a full-featured Webmail client along with resource sharing and permission handling. It also makes use of documented standards (CalDAV, CardDAV and GroupDAV, vCard, and vCalendar/iCalendar) and thereby enables the use of many clients and the reuse of any existing infrastructure. The appliance is prepared to be imported in VirtualBox but can also used in VMWare.