Arcavias is an e-commerce framework for Web shops, consisting of an e-commerce library, an administration interface, and different frontends. It's a modular stack which offers flexibility and speed. Unlike other Web shops, it's not a monolithic application. Instead, you have a choice between several user frontends, and you can adapt them to your needs or write one of your own.
Kolab is a groupware system that provides a comprehensive and flexible solution for workgroups. Email, contacts, and group calendars can be managed via the Web, Windows/Outlook, and Linux/KDE. It supports offline synchronization and full seamless support of mixed client environments because the Kolab-XML storage format is fully open and avoids MAPI/TNEF.