17. An apparatus for implementing a user interface adapted to visually indicating on a display those documents that have been copied from one axis of documents to another axis of documents based on a user-selected attribute, the apparatus comprising: a memory module adapted to store thereon a plurality of documents; and a processing unit in communication with the memory module, the processing unit being operative for executing computer readable program code stored on a non-transient computer readable medium for implementing a method comprising: (a) displaying documents of the plurality of documents on a first axis of documents; (b) with respect to a first user-selected attribute of one of the first group of documents that is associated with one or more attributes, (i) receiving user input representing the first user-selected attribute; (ii) copying to a second axis of documents each document of the plurality of documents that has the first user-selected attribute, at least a portion of the second axis being displayed at least during a period of time in which at least a portion of the first axis is displayed; and (iii) displaying for a predetermined period of time a visual distinctive feature associated with each displayed document on the first axis that is copied to the second axis; whereby a user is able to visualize which documents along the first axis have been copied to the second axis; and (c) with respect to a second user-selected attribute of one of the first group of documents that is associated with one or more attributes, (i) receiving user input representing the second user-selected attribute; (ii) copying to a third axis of documents each document of the plurality of documents that has the second user-selected attribute, at least a portion of the third axis being displayed at least during a period of time in which at least a portion of the first axis is displayed; and (iii) displaying for a predetermined period of time a visual distinctive feature associated with each displayed document on the first axis that is copied to the third axis; whereby a user is able to visualize which documents along the first axis have been copied to the third axis.
20. The apparatus of claim 17 , wherein the method implemented further comprises displaying an animation showing a movement of one or more of documents that are copied from the first axis.