Trello - The coolest of collab tools!

An online, free, Web 2.0 application I've been utilizing for the better part of 4 years now has been Trello. It's a group messaging board with a TON of potential and flexibility. I use it for backend asset management, group projects, classroom "lecture" applications and even an online casting sheet!

Currently I'm taking the EME5608 class and created a board for our group (Team Awesome). You can check out our progress here. The UI is intuitive and easy to understand. There's also an app that will keep you notified whenever someone sends you a message/updates a card.

Let me know what you think about Trello in the comments below. Have you used it before? Have any questions about it? Are there other online applications that you use that are similar/better?