RTM is basically a TODO list on serious steroids. It's the Swiss Army Knife of task management. It allows you to manage multiple lists of tasks. You can add them easily from a variety of mediums, tag them, prioritize them, set deadlines for them, have them repeat, get reminders for them, tie them to physical real world location, and share them.
He's even already issued a proposal for the functionality to the project to hep further along its inclusion. His goal is to get it included in the core for the framework within the next two releases.