Todoist’s To Do list service helps organize your tasks across many platforms, from laptop to tablet to smartphone. The service includes the website and the app, and both are simple to use. For a free App it is great, I highly recommend it to anyone who needs help keeping track of their to do list.
You can divide your to do’s into separate checklists, which ToDoist calls “Projects”, within each project you can assign a number of tasks. After you complete a task, you can check the box next to it, and it will disappear from your list.
One of the neat things about ToDoist is that you can track your progress and productivity over time. ToDoist remembers what tasks you completed on what day, and compiles a productivity chart that you can view, called ToDoist Karma (this screenshot was taken from the ToDoist browser app).
The below is a screenshot of my productivity graph that ToDoist emailed me:
Make sure to check it out!