ability to divide a task into mutiple subtasks is very useful

When I assign a task to someone, many times that task needs to be broken down further, and some of those subtasks need to be assigned to some other members in the company. So I think having an ability to create subtasks very will be very useful.

Especially, when the number of project team members exceeds 20 to 30, dividing and delegating tasks become very important. Having a single depth of tasks isn't going to cut it in the cases where many team members with different ranks in the company hierarchy are working together.

I think goplan.org has implemented this idea very well.

1) only the assignee of a task can create subtasks
2) any task (or subtask) can have muliple subtasks