Yes, I was trying to say that developing Trello is still really fun, even as it's getting bigger - we are starting to see some minor scaling challenges, but it's still a great time.
But we do use Trello to manage Trello, with a public dev board (https://trello.com/dev) and also internal boards to track things that are not yet public or that are too granular to expose externally.
And there are a bunch of good articles about how people are using Trello; searching for 'How I use Trello' turns up a lot of ideas. That being said, it's not going to fit everybody every time.
Took a look at the dev board as a way to "demo" the service without signing up. It seems... overly complicated? Maybe I really do just need to sign up.
Care to tell us how you use it?