I use Emacs' org-mode to keep myself organized, and have generally disliked all other task list applications — they usually lack flexibility or require unhelpfu

I use Emacs' org-mode to keep myself organized, and have generally disliked all other task list applications — they usually lack flexibility or require unhelpful and distracting self-adjustments to fit their worldview. Trello feels like web-based org-mode. For simple use, it is almost as flexible, and it has groups and sharing built in. Nicely done.