HeySpace - HeySpace is the only free task and simple project management software with communication and collaboration feature.
Mighty Networks - Mighty Networks enables entrepreneurs, organizations, and companies to create and grow a community-powered brand.
Rivers IM - Simple, fast & secure team collaboration platform
Bigtent - BigTent is a web-based organization and communication portal for groups.
P2 - Share, discuss, and collab with your team. By Wordpress.
Nabble - Nabble is a forum software that are embeddable and fully customizable with scripting language.