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Kanbanize - Kanban Software that scales your business!
Kanban Tool - Simple and effective online application for visual project management.
Huntr - A Kanban board for your job applications
Wekan - The open-source Trello-like kanban (built with Meteor)
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.