Personally, I do not think there is anything more irritating during a release or iteration planning session than watching a non-typist editing user stories and tasks in a web-based product. If you want to kill all the energy and interaction during collaborative planning, retrospectives, and design sessions then all you have to do is connect a laptop to a projector and crank up a typical, web-based agile project management tool.
These tools are not designed to be used during collaborative sessions. They hand too much control to the person with the keyboard. Use low tech tools during face-to-face, creative meetings. Type up the results afterwards.