GanttProject is open source Java based, project management software that runs under the Windows,Linux and Mac OS X operating systems. It features most basic project management functions like a Gantt chart for project scheduling of tasks, and doing resource management using resource load charts. It does not have advanced features like cost accounting, message and document control. It has a number of reporting options (MS Project, HTML, PDF, spreadsheets).
Trello uses the “kanban paradigm” for managing projects, originally been popularized by Toyota in the 1980s for supply chain management. Projects are represented by boards, which contain lists (corresponding to task lists). Lists contain cards (corresponding to tasks). Cards are supposed to progress from one list to the next (via drag-and-drop), for instance mirroring the flow of a feature from idea to implementation. Users can be assigned to cards. Users and boards can be grouped into organizations.
It operates a freemium business model, as well as being cross-subsidized by other Fog Creek Software products. A basic service is provided free of charge, though a Business Class paid-for service was launched in 2013.