Trello is a task manager built around the concept of ‘Kanban’ which is essentially a scheduling system that allows you to move your tasks from one state to the next.
The interface is built around the concept of a ‘Task board’ with columns for each state a task might be in (for example “to do, in progress, done”). The workflow is then to move tasks from one column to the next.
Pro Free for unlimited users
Trello offers a very generous free version that has no ads, no restrictions on the number of users, and very little restriction on how the program can be used. The paid features are generally cosmetic, such as the ability to change the background, add stickers or integration with other tools.
Pro Simple and easy to use interface
There are two primary columns: the board is shown on the left and all the other controls on the right. The main means of interaction is dragging and dropping to-do cards into the various lists.
The board structure is very customizable, and includes a variety of features that help along the way: color-coding, due dates, card images, checklists with a graphics bar that allows following progress easily, and card aging for cards that haven’t been touched in a long time.