I know, but it was usable when I last used it. (and it was not designed by Atlassian AFAIK... and even if it would, I don't have anything against Atlassian except that they make really terrible software which I was quazi-forced to use)
Trello was founded by Joel Spolsky, the guy who made stackoverflow, and was sold to atlassian
He also made Fogbugz, which apparently still exists although I never hear anyone talk about it.
Its been getting slower and more cumbersome since they bought it.