The Floranta AJAX libraries are used to build Rich Client Wikis. Editable sticky notes can be created and positioned over any Web page (even plain HTML), and are capable of behaving as if they stored their entire state in the page. Floranta enables collaborative teamwork and creative activities like cartooning and collage creation, personal notes, ToDo lists, and blogging.
Seir Anphin is a CMS focused on developing communities. Its core is a versatile platform for building any kind of site, but there is also a set of modules which provide features for building social networking hubs and communities. These modules integrate themselves during installation automatically, so you can just choose the features you need: forums, blogs, events calendar, file sharing, image gallery, and advanced article publishing.