Trello is a great low-cost, clean, aesthetic, cross-platform (web, iPhone, iPad, and Android) team collaboration tool designed to be as simple and intuitive as possible.

Utilizing Boards (projects) and cards (tasks), Trello solves about a dozen problems all at the same time over grid-oriented task lists, including: scanning to-do lists repeatedly, confusion about priorities of assignments, inability to see updates on what has changed in to-do lists, better team visibility and empathy on workloads, consolidating multiple lists used to compartmentalize, automatic reporting back and accountability, easy and persistent commenting around tasks that doesn’t get lost, and several other needs.