http://trello.com http://trello.com and http://teambox.com http://teambox.com (beta at http://beta.teambox.com http://beta.teambox.com) have a common ancestor:

http://trello.com http://trello.com and http://teambox.com http://teambox.com (beta at http://beta.teambox.com http://beta.teambox.com) have a common ancestor: http://www.pivotaltracker.com http://www.pivotaltracker.com That was the first widely adopted kanban tool for developers that I know about