Twitter-Like Project Collaboration Tool: Teambox
Teambox is an open source platform that enables teams to collaborate on projects with a Twitter-like interface.
The application is built with Ruby on Rails and, besides the open source version, has a hosted version too.
Users can create an unlimited number of projects & tasks, assign them to their colleagues, share messages, files & much more.
Users can start a conversation instantly, create pages to store information & Teambox can integrate clients to the system to colaborate with them easily.
The application is multilingual, has support for mobile phones & offers a read-only API for integrations with 3rd party softwares.