1. A system for collaborating among a plurality of users each at an associated one of a plurality of computing appliances each comprised of a non-transitory memory and an input apparatus providing for user input, the system comprising: input logic permitting concurrent input via the input apparatus by at least two of the users, to provide annotation data having an associated image for display; layer logic structuring storage in the memory of each of at least two of the computing appliances, as a plurality of data layers duplicated in each of said computing appliances, wherein each said user is associated with a same said data layer in each of the computing appliances; control logic storing the annotation data associated with each said user in the associated said data layer that is associated with each said user, for each of at least two of the users; display logic, selecting at least two of the plurality of said data layers as selected data layers; display generation logic responsive to the annotation data from the selected data layers to generate a display presentation for viewing by at least one of the users.