I was thinking of a new collaborative way to keep people on tasks but not distracted with reading or manipulating talks. I feel the biggest reason "todo apps" don't work is because the are "procrastinating-dos". I might design a todo app where you may share with friends or co-workers to help keep track of what everyone is doing, but without the hassle of really depicting each task. Everyone on a team should have a goal, whether it be a shared goal or an individual one, you must have tasks that make up that goal. After a goal is complete (meaning all tasks under that specific goal are done as well) the team should review how well that goal was executed. Maybe in the near future somebody will do it. But if that is not the case, I might look into it more.
I'm a big fan of "Things" for iOS and OS X. I like being able to drag and drop items into different categories, cloud syncing (I always have it on my desktop and iPhone), and scheduling tasks (particularly recurring tasks) is great (1st saturday of every month, every tuesday, etc.).
I'm still waiting for the perfect app to have with my husband so that we can share to-dos and import/export calendar items and get notifications on the phone/desktop. Something that an app like Pair should be a perfect home for but they don't really focus on that.