Abstract:
The present invention teaches methods and apparatus for social interaction allowing users to communicate at their leisure (asynchronously or “semi-synchronously”) by providing simple, flexible access to a persistent, shared space. For example, an electronic communication system according to one embodiment provides a shared persistent data space to a plurality of clients. This system comprises a server and at least two input/display units (IDUS) which clients use to access shared persistent data in the form of group boards. The group boards store discrete notes in a group database made accessible to all members of the group. In order to allow clients to select a desired group, each IDU includes an input detection space operable to receive user input indicative of a request to access a specific group. The input detection space can take on many forms such as electromechanical buttons, touch or pressure sensitive devices, a digital inking device, a token input device (tokens each have some identification in the form of circuitry or such), or a voice command device. In order to allow clients to enter data into the board group database, each IDU includes a note data input device. Like the input detection space, a wide variety of note data input devices are contemplated. For example, a touch, stylus or pressure sensitive device would be suitable. A scanning device also works well, creating a unique persistent space wherein users can exchange discrete note messages of a variety of forms such as handwritten notes and photographs.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application is related to and claims priority of U.S. Provisional Patent Application No. 60/062,144 filed Oct. 9, 1997, incorporated herein by reference. This Application is also related to and claims priority of U.S. Provisional Patent Application No. 60/001,875 entitled METHODS AND APPARATUS FOR REMOTE SOCIAL INTERACTIONS filed Oct. 8, 1998, incorporated herein by reference. This Application is also related to U.S. patent application Ser. Nos. (a) Ser. No. 08/610,638 now U.S. Pat. No. 5,889,843 filed Mar. 4, 1996, (b) application Ser. No. 09/169,839 entitled METHOD AND APPARATUS FOR SENDING PRESENCE MESSAGES filed Oct. 9, 1998, (c) application Ser. No. 09/169,713 entitled ELECTRONIC AUDIO CONNECTION SYSTEM AND METHODS FOR PROVIDING SAME filed Oct. 9, 1998, and (d) application Ser. No. 09/169,713 entitled VARIABLE BANDWIDTH COMMUNICATION SYSTEMS AND METHODS filed Oct. 9, 1998, all four being incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to group communication systems, and more particularly to electronic group communications systems for remotely linking two or more geographically separated spaces for social interaction. 
     2. Description of the Related Art 
     Electronic communication systems technology provides an incredible number of ways for people to communicate with each other. Everyday examples of such communication systems include telephones, answering machines, and pagers. Communication systems that are adapted for the workplace include computer network file-sharing, electronic mail (“email”), fax machines, electronic whiteboards, and telephone and video conferencing. Important classes of these systems include asynchronous document-management systems and synchronous conferencing systems. 
     Asynchronous document-management systems enable users to exchange email and access shared databases to create, read, and revise documents. Because these systems manage documents that persist over time, users of these systems can work independently from one another; for example, one can send an email message at any time of day, without having to take into consideration the recipients&#39; accessibility at the time of sending. Synchronous conferencing systems typically connect together sets of users at the same time in order to have a joint verbal discussion using shared audio and/or video channels. Often these systems provide a shared “whiteboard” channel as well, on which users can draw using “digital ink” and move a shared pointer to refer to portions of these drawings during the conversation. 
     FIG. 1 is a diagram of a conventional asynchronous document-management system  10  of the prior art. The system  10  includes a server  12  and a plurality of clients  16  coupled together by a network cable  18 . The server  12  is typically a computer with substantial processing power and storage capacity. The server  12  stores and maintains a large number of documents  14  that are made available to the clients  16  over the network cable  18 . Each individual client  16  is usually a terminal that can be operated by a single user such as a personal computer or a workstation. 
     The server  12  and the set of clients  16  are able to transfer and copy the documents  14  between them. The documents  14  may be any form of information or data such a word-processing documents, programs, and graphics. The network cable  18  is a communication line that is configured to transfer the documents  14  electronically between the server  12  and the clients  14  such as a phone line or an Ethernet cable. 
     The document-management system  10  has been very successful at providing a high-speed means for sharing information. In addition, software known as groupware increases flexibility of the shared information within the system  10 . One of the most successful groupware applications is Lotus Notes, which allows a workgroup to share documents jointly and to add notes commenting upon these documents in a structured way. However, these systems are optimized for handling large quantities of typewritten textual information and thus can be cumbersome to maintain and use. 
     FIG. 2 is a diagram of a conventional synchronous conferencing system  20  of the prior art. Microsoft Net Meeting is one example of a conferencing system  20  that includes clients  22  that are connected by a network cable  24 . For ease of illustration, only two clients  22   a  and  22   b  are shown, however, as is well known in the art, many more clients  22  can be connected to the cable  24  to allow more users to join the conference. Users of the conferencing system  20  are able to communicate directly with each other to view and modify a shared “whiteboard” document  26  at the same time through the clients  22 . 
     FIG. 3 is a flow diagram of a synchronous conferencing system  30  of the prior art. The conferencing system includes a server  32  that is connected to a number of clients  34 . For ease of illustration, only two clients  34   a  and  34   b  are shown, however, as is well known in the art, many more clients  34  can be connected to the server  32 . The server  32  maintains an updated-shared document  36  that is available to the clients  34 . When the users “hang up” and disconnect from the conference the updated-shared document  36  is not automatically saved. 
     While synchronous conferencing systems enable users to jointly view and modify documents at the same time many lack a quality known as persistence which is inherent in all asynchronous systems. For example, when an email message is received, the content of the communication must be persistent because it is generally not read immediately. Because the message is saved on the receiving computer the recipient can then read, print, or respond to the message at her leisure. 
     In contrast, because synchronous communication focuses upon real-time coordinated interaction, the content of the shared whiteboard document in most synchronous conferencing systems is ephemeral. Generally, when all of the users disconnect from a synchronous system, the content of the shared document is lost. There are electronic communication systems that allow for the preservation of the shared document, however the prior art methods for doing so are not very flexible and generally require an explicit request from the user. 
     In summary, prior art asynchronous document-management systems allow users at their leisure to exchange messages at their leisure and jointly add to, read, and revise a persistent shared database, but require users to follow formal and cumbersome procedures designed to enable large text-based databases. Prior art synchronous conferencing systems allow sets of users to converse in real-time and provide easy, flexible access to a shared digital-ink-based whiteboard document. However, they require the conversing users to use the system all at the same time, and are not easily configured to save the content of the shared document. In view of the foregoing, it is desirable to have a method and apparatus of social interaction that provides for an easy-to-use means of communication combining aspects of both asynchronous document-management systems and synchronous conferencing systems. 
     SUMMARY OF THE INVENTION 
     The present invention fills these needs by providing an efficient and easy to use method and apparatus of semi-synchronous communication. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device or a method. This method and apparatus of social interaction allows users to communicate at their leisure (asynchronously or “semi-synchronously”) by providing simple, flexible access to a persistent, shared space. Several embodiments of the present invention are described below. 
     A first embodiment of the present invention takes the form of an electronic communication system that provides a shared persistent data space to a plurality of clients. This system comprises a server and at least two input/display units (IDUs) which clients use to access shared persistent data in the form of group boards. The group boards store discrete notes in a group database made accessible to all members of the group. The server may be centrally located separate from the IDUs or, alternatively, the server may be a virtual server distributed across the IDUs. In any event, the server maintains at least one group board database thereby creating a shared persistent space accessible by the IDUs. 
     In order to allow clients to select a desired group, each IDU includes an input detection space operable to receive user input indicative of a request to access a specific group. The input detection space can take on a wide variety of forms such as an array of electromechanical buttons, a touch or pressure sensitive device, a digital inking device, a token input device (tokens each have some identification in the form of circuitry or such), or a voice command device. 
     In order to allow clients to enter data into the board group database, each IDU includes a note data input device. Like the input detection space, a wide variety of note data input devices are contemplated. For example, a touch, stylus or pressure sensitive device would be suitable. A scanning device also works well, creating a unique persistent space wherein users can exchange discrete note messages of a variety of forms such as handwritten notes and photographs. 
     The present invention also teaches a variety of methods for operating the electronic communications systems described above. For example, certain methods enable multiple boards to be accessed by a single IDU. In the case of the token input detection space, the input detection space is capable of receiving and detecting multiple tokens in order to access more than one board group. 
     The present invention also teaches the creation and maintenance of electronic database through the use of a scanning input device. Using the scanning input device for data entry enables the database client to assemble numerous discrete notes of varying type within a single database. E. G., the notes could be scanned photographs, handwritten notes, word processor documents, etc. This enables the database client to assemble, view and manipulate data arising from a wide variety of sources. 
     Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. 
     FIG. 1 is a diagram of a asynchronous document management system of the prior art. 
     FIG. 2 is a diagram of a synchronous conferencing system of the prior art. 
     FIG. 3 is a flow diagram of a network conferencing system of the prior art. 
     FIG. 4 illustrates one embodiment of a control unit of the present invention, which is known as PinBoard. 
     FIG. 5 is a block diagram of a pinboard electronic communications system in accordance with one embodiment of the present invention. 
     FIGS. 6-7 illustrate two particular PinBoard devices. 
     FIG. 8 is a diagram structure of several boards with multiple members, the structure in accordance with another embodiment of the present invention. 
     FIG. 9 is an illustration of a logical representation of a token in accordance with yet another embodiment of the present invention. 
     FIG. 10 is a diagram of a logical representation of a board database within a storage unit in accordance with still another embodiment of the present invention. 
     FIGS. 11A-11C illustrate three screen shots of a PinBoard display. 
     FIG. 12 illustrates an input/display unit (IDU) in accordance with another embodiment of the present invention, known as ScanBoard. 
     FIG. 13 is a screen shot of the touch screen display of the ScanBoard IDU of FIG.  12 . 
     FIG. 14 is a flow chart illustrating a client server communication protocol in accordance with one aspect of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A method and apparatus for semi-synchronous communication within a shared persistent space is disclosed. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. One skilled in the art will understand that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention. 
     FIG. 4 illustrates an input/display unit  100  of one embodiment of the present invention, which is known as PinBoard. The input/display unit (IDU)  100  is generally mounted on a wall  102  or any other suitable flat surface such as a table or even a refrigerator door so that a user  104  has easy access to the IDU  100 . The IDU may also be a software product for use on a desktop computer. In this example, the IDU  100  includes a frame  106  and a touch screen display  108 . The user  104  is able to input data directly to the IDU  100  through the touch screen display  108 . As described below with reference to FIG. 5, the IDU  100  is networked together with other IDUs  100 . 
     By pressing a stylus  110  against the touch screen display  108 , the user  104  can write a message to other users as shown on an enlarged view  112  of the touch screen display  108 . The data input by the user  104  is carried to other IDUs  100  by a PinBoard network. The other users may see the message written by the user  104  after a short delay if they are viewing the touch screen display  108  of their own IDUs  100  at the time of reception, or they may see the message at some later time. It is in this manner that the present invention allows access to a shared persistent space by a number of users. 
     FIG. 5 is a system diagram of a PinBoard network  114 . The PinBoard network includes multiple IDUs  100  and multiple storage units  116  connected together by one or more transmission mediums  118 . Examples of transmission media  118  include wireless modems, a plain-old-telephone-service (POTS) or ISDN connection, and the Internet. The IDU  100  preferably includes input devices  120 . Examples of specific input devices  120  include a microphone, a camera, a scanner, and the stylus  110 . Data from the PinBoard network can be output through the touch screen display  108  and/or set of speakers  122 . 
     The IDU  100  also includes a set of tokens  124 , and a token holder  126 , which in this example is a Velcro surface on which the tokens  124  are mounted. The tokens  124  are generally objects that can easily be held between a user&#39;s thumb and index finger such as a simple push button. The tokens  124  are activated when data on a storage unit  116  is modified. The tokens  124  preferably indicate their state by for example, glowing brightly when a modification has occurred. The user may then use the tokens  124  to request and display data from the storage units  116 . After examining the transmitted data, the user may then make modifications using one of the input devices  120 . 
     FIG. 6 illustrates one embodiment of the IDU  100   a . The IDU  100   a  has a frame  106   a  that includes a number of cradles  128 , which function as a place to hold and store tokens  124 . The frame  106   a  also features a slot  130  where tokens  124  can be inserted to request and display data from a storage unit  116 . FIG. 7 illustrates another embodiment of the IDU  100   b . The IDU  100   b  has a frame  106   b  that includes a number of slots  132 . Tokens  124  are stored in the slots  132 , and can be pushed down into the slots  132  to request data from a storage unit  116 . The tokens  124  may also be removed. 
     FIG. 8 is a diagram of a number of members  134  and a number of boards  136  on the PinBoard network  114 . John Doe is a member  134  of all of the boards  136  including the Local PTA board  136 , the Friday Club board  136 , the Soccer Team board  136  and the Doe Family  136 . Each board  136  has its own number of members  134  that John can communicate with by using the boards  136 . For example, John can communicate with Uncle George by using the Doe Family board  136  and vice versa. Uncle George also happens to be a member of the Local PTA board  136 , and John could conceivably leave a message for him there as well. However, that message would also be visible to all the members  134  of the Local PTA board  136 . These transactions can occur by manipulating the tokens  124  as described below. 
     FIG. 9 is an illustration of a logical representation of a token  124 . Each token  124  includes a user identification  138  and a board identification  140 . Continuing from the above example, if John wants to access the Soccer Team board  136 , he would use the token  124  that contains the board identification  140  for the Soccer Team board  136  to command the IDU  100  to access the correct storage unit  116  and the correct board  136 . The token  124  allows John to request data from and to the Soccer Team board  136 . 
     John&#39;s user identification  138  would be input so that he could be identified to other members  134  of the Soccer Team board  136  as the member  134  making modifications. 
     In addition to its functionality, tokens may also be shaped to represent each board  136 . For example, the Soccer Team board  136  could be represented by a token  124  that is shaped like a soccer ball. Tokens  124  provide a way for members  134  to express themselves and the social relationships they have. For example, high school sweethearts could share a board  136  between themselves and access the board  136  with heart shaped tokens  124 . The Local PTA board  136  could be accessed with tokens  124  that are shaped like a school house or a book and so forth. 
     FIG. 10 is a diagram of a logical representation of a board  136  within a storage unit  116 . Boards  136  are stored and maintained by storage units  116  which transfer data to IDUs  100  as described above. Each storage unit  116  may include a number of boards  136 . Each board  136  then further includes a number of notes  142 . Each note  142  is a contribution to the board  136  from an individual member  134 . All the members  134  with the correct board identification  140  in their token  124  may view the board  136  and all the notes  142  that are on it at the given time. 
     Referring back to FIG. 5, an IDU  100  preferably implements the following functions: request (and display) contents of boards  136  from a storage unit  116  when its token  124  is pushed; activate attached token  124  when notified that corresponding board  136  has been modified; record, play, and edit notes  142  on currently displayed board  136 ; send new or modified notes  142  to the storage unit  116  for storage and propagation to other IDUs; and request the storage unit  116  to create or delete a board  136 . 
     A storage unit preferably includes a storage medium (e.g., disk), a modem or other communication device for connecting to IDUs, and a processor that runs the control software. A storage unit acts as a file server, implementing the following functions for each board it serves: send board contents to the IDU; receive board contents from the IDU; add the IDU to or delete the IDU from owner list of the board; send notification that the board has been modified to the IDUs on its owner list; and create or delete the board. The IDU and the storage unit may be packaged together as a single appliance, or the storage unit may be provided by a centralized service that IDUs call into. 
     There are various kinds of notes, including ink notes produced by freehand drawing on an input surface, typically contain handwriting and drawings; text notes produced by typing on a keyboard, or by applying optical character or handwriting recognition to an ink note or scanned document; and audio notes produced by recording into a microphone. Other types of notes include image notes which produced by electronic cameras or scanning, such as comic strips; video notes which are produced by recording into a microphone and video camera. Background notes are a special kind of ink notes, which serves as the background for a board. 
     The following actions can be performed on notes: (1) record/create; (2) attach to existing note (e.g., as a reply); (3) play/enlarge; (4) pin to board (add to the storage unit from local copy on the IDU); (5) unpin from board (remove from the storage unit, and maintain only as a local copy on the IDU); (6) move to new position on board; (7) delete; (8) export into token; and (9) import from token. 
     In one preferred embodiment, notes are attached to a board. The board is a shared virtual surface on which notes can be pinned. Associated with it is a list of IDUs who own it. When the list changes, the IDUs for all owners are notified. Boards have distinctive, patterned backgrounds that can be written on. The “pins” are small graphical icons that appear on a note that can specify which user produced it. The border of a note is black when first pinned, and gradually fades as time elapses. Thus, a quick glance at a note can furnish information about who posted it and when. 
     Alternate embodiments of the PinBoard include: multiple boards; more than two households connected; more than one IDU per household; disk storage of messages; active objects or tokens; and the visual “aging” of messages. One close variant includes a single shared surface for all members of an interconnected group. This has an advantage of simplicity, as multiple boards need not be managed. However, this embodiment constrains all members of an interconnected group to be completely interconnected, which sometimes is not desirable. Consider households A and B, both of which want to communicate with household C, but which themselves have no desire to communicate. A single-board system would force A and B to be connected to each other to the same degree they are connected to C. 
     FIG. 11A is a screen shot of a PinBoard display  144 . The PinBoard display  144  includes two messages from a remote IDU are displayed on a local IDU, namely a note  146  time-stamped 7:38 inquiring if Scott was there, and another note  148  time-stamped at 8:00 relaying that Scott has “finally woke up.” When note  148  is posted, it preferably appears in the area of the PinBoard display  144  where created by the user. 
     FIG. 11B is a screen shot of a PinBoard display  150  showing restricted screen availability. In this embodiment, users cannot over-write each other&#39;s postings and, since the screen is full, something must be “erased” or a new screen must be brought up in order to create new postings. In other embodiments, over-writing or layering is allowed. In a preferred embodiment, each note can have a rectangular border, and lay over the top of older notes. The users have control how the notes are displayed and are able to move each note by clicking and dragging it with a finger on the touch screen display. 
     FIG. 11C is a screen shot of a PinBoard display  151  showing structured sequencing. A problem in determining the chronological order of messages can occur if messages are randomly written to the screen. With this structured sequencing embodiment, the messages are time-stamped and provided in chronological order so that the sequence of messages is apparent. It is preferred that the time stamping is an automatic function of the system, but the time stamping can also be entered manually by the users as an informal custom. 
     FIG. 12 illustrates an IDU  152  in accordance with another embodiment of the present invention, known as ScanBoard. The IDU  152  includes a frame  154  and a touch screen display  156 . A set of control buttons are mounted on the frame  154  including a series of group area buttons  156 , a forward button  158 , a backward button  160  and a system button  162 . The group area buttons  156  function in the same manner as tokens  124  in the PinBoard network  114  of FIG.  5 . The frame  154  also includes a scanner slot  164  that allows access to a scanner that is configured to fit inside the IDU  152 . 
     A ScanBoard network of the present invention includes of any number of clients running on custom scanner/display appliances and servers running on standard computer hardware, connected together by some transmission medium such as telephone lines, wireless modems or the Internet. Thus, the system may be configured in a similar fashion as the PinBoard network  114 . Message items are accumulated and accessed according to “group areas” which are similar to boards in function. A group area is a layered heap of thumbnail images of scanned items, together with a list of group members who may access the area. 
     The IDU  152  implements the following functions: request (and display) the current contents of a group area from a server; turn on a “message waiting light” when notified by a storage unit server that the group area has changed; scan an item, manipulate scanned item, and display locally; send scanned item to server for “publication” to other IDUs in the group area; move the location of items within and across group areas, and notify the storage unit server of changes; and create, remove, or modify the group area or list of users who may access it. 
     FIG. 13 is a screen shot of the touch screen display  156  of a ScanBoard IDU  152 . The user interface resembles a bulletin board comprising images that have been scanned into the system. The appliance&#39;s display can be in one of two states: a shared view of a group area or a local view of a single item. The shared view consists of a “pile” of potentially overlapping items, displayed in a photo-reduced, “thumbnail” form. If two items overlap, the one at the higher level occludes the one at the lower level. All users in a group area share the same shared view. When an item is displayed with a local view, the screen shows only that item, in photo-magnified form. 
     When a user scans in an item, a thumbnail version of it is placed at a random position at the top of the shared pile currently displayed on the user&#39;s screen. The new item occludes all of the items beneath it. The user&#39;s own display updates immediately to show the new item. The server is notified about the new item and proceeds to update the displays of the other members of the group area. 
     When a new item appears in a group area to which the user has assigned one of their IDU&#39;s  152  group area buttons  156 , that button lights up. To switch their IDU  152  to access a group area, the user presses the associated button. To assign a group area to a button, the user navigates to the group area by using on-screen controls and then holds down the group area button to be assigned to it until they hear a beep. 
     To get a local, magnified view of an item, the user taps their finger on the item through the touch screen display  156 . While in local view mode, the item may be moved around the screen by “dragging” it with one&#39;s finger (or stylus) on the touch screen display  156 ; this allows all portions of the item to be seen, even if it is too large to fit on the screen. There are multiple ways to exit the local view and return to a global view including: tapping the screen; waiting for the display to return to a global view after a timeout period; and pushing a group area button. 
     When the appliance is displaying an item in a local/magnified view, the user can change the item being displayed by pressing the forward or backward buttons  158  and  160 . Pressing the forward button  158  switches the IDU  152  to displaying the item in the layer immediately above the current item; pressing backward button  160  switches the IDU  152  to displaying the item in the layer immediately below. 
     When the appliance is displaying a group area, upper layers may be removed to reveal what is (potentially) being occluded below them by pressing the backward button  160 . Each press removes the currently displayed top-most layer. Similarly, the forward button  158  causes the layer above the currently displayed top layer to be displayed, reversing the effect of the backward button  160 . If the backward button  160  is pressed with no layers currently displayed, or if the forward button  158  is pressed if no layer exists above the currently displayed top level, nothing happens except for a clicking sound. Holding the backward or forward buttons  158  and  160  down for a second or so causes an “auto-repeat” mode, so layers are quickly, successively removed or restored. The display will revert to showing all layers if no activity occurs for about 30 seconds. 
     Instead of tapping on a thumbnail in the global view to display it, the user can select it by pressing their finger on it for a short period (about 1 second). The selected item is marked with an icon that appears to float (at the highest level in the heap) above the item&#39;s upper left comer. Clicking on this icon will de-select the item. (The item will automatically be de-selected after some period of inactivity has passed.) Only one item can be selected at a time. When a user scans in a new item, it is initially selected automatically. 
     A number of global operations can be performed on a selected item. To move the selected item in the x-y plane, the user “drags” it with their finger or stylus. To increase or decrease the selected item&#39;s level in the “pile”, the user presses the forward button  158  or the backward button  160 . To move the selected item to a new group area, the user presses the button for that group area. The item is then deleted from the original group area, and added as the top level of the new group area. (If the user changes their mind and wants to return the item to its original group area, and the item has not become de-selected, they can accomplish this by pressing the button for the original group area. Then the item will be returned there at its original level.) To delete the item, the user presses the system button  162 . a pop-up window appears with on-screen buttons to perform various infrequent tasks, one of which is “Delete Selected Item”. Unless an item is locked, it can be deleted by any user with access to the group area it appears in. To lock the item, the user presses the system button  162  and then further presses an onscreen button that appears in the pop-up window. 
     When an item becomes de-selected, the appliance checks if its location (group area, level within group area, and (x, y) position) has changed. If so, it contacts the server to update the information there. The server in turn notifies all of the appliances connected to that group area that the group area has changed. When notified of a change, the appliance downloads the updated information and updates its own cache accordingly. 
     A number of days after an item was last created (or de-selected), the server marks it for archiving. Items marked for archiving are displayed as translucent, and they become more and more transparent until they actually become archived, at which point they disappear from the group area entirely. (From the controls on the pop-up window that appears when the user presses the system button  162 , the user can retrieve items from the archive.) As described, the interface provides a set of local and global functions. Local functions affect only the individual user&#39;s display; global functions affect all the users of a group area. 
     Local functions include: switching between “display single item,” “select single item,” and “shared view” modes; uncovering/recovering layers in “shared view” mode; change layer being displayed in “display single item” mode; move item being displayed in “display single item” mode; change group areas being displayed in “shared view” mode; assigning or reassigning group area to group area button. Global functions include: scanning item into group area; moving item within group area; moving item between group areas; deleting item from group area; restoring item from archives to group area; and locking item in group area. 
     An alternative embodiment of the ScanBoard is a handwriting-only system, based on a shared whiteboard on which users directly “write” using a stylus that creates “digital ink.” (See for example, the PinBoard description, above.) ScanBoard is superior in that richer media types (e.g., snapshots and newspaper clippings) can be exchanged between users, making for a richer user experience. Because ScanBoard requires only simple touch interactions, and not high-sample-rate pen input, its digitizer/display is somewhat less expensive. Directly writing on the screen, to add content to new blank items or to previously scanned items, may be a desirable feature to add to ScanBoard, to get the best of both interface paradigms. 
     Another alternative embodiment replaces the touch screen with an ordinary, output-only display. Items are displayed, selected, and otherwise manipulated by means of buttons, a mouse or mouse-equivalent, or both. (One possibility would be to permit display, selection, movement, etc., of only the top level item; the user would use the forward or backward buttons  158  or  160  to place the item of interest at the top level, and then additional buttons (Display, Move, Delete, etc.) to operate on this item.) However, using a touch screen is believed to create a more immediate and satisfying user experience. 
     Yet another alternative is to use a conventional tube display, rather than a flat-panel touch screen. For example, the appliance can look (and function) as an ordinary television. Compared to this, the flat panel solution has advantages in weight and ease of mounting on a wall, though it would be more expensive. Ordinary TV displays would also suffer problems in resolution. 
     Instead of a scanner, the user can use some other device for entering images into the system, such as a digital camera or graphics file email attachment. Digital cameras have some advantages to scanners, and a plug for digital camera input is considered to be a valuable extension to ScanBoard. However, digital cameras are not well suited for capturing printed documents. Email attachments or other mechanisms for remotely sending images to a ScanBoard also have their place, but lack the immediate gratification of seeing printed/handwritten material immediately transformed into digital form on the ScanBoard screen. 
     Yet another alternative embodiment provides a software-only system, the users having to provide their own hardware (display, scanner, other is input devices). However, existing hardware is not adapted for the kind of image sharing/messaging interactions that the ScanBoard software provides. For example, conventional PCs are usually located in parts of the house that are inconvenient for checking and leaving messages, and are not left on continuously. 
     In solving a communication problem, ScanBoard solves a database access problem: how to provide a simple mechanism for displaying to a group of authorized users a large number of discrete items, allowing those users to act upon them. This kind of database access problem arises in many situations such as in presenting email messages, or the results of a database query, or the options for viewing one of many television channels, or the contents of a file system. 
     By modifying the kinds of data that are entered into the system and the mechanisms for display and manipulation of data items, ScanBoard-like interfaces could be used in a wide range of applications, such as shells for operating systems. The ScanBoard has a number of valuable uses. For example, ScanBoard&#39;s functionality is a valuable addition to PCs (or other in-home “information appliances”). A stand-alone ScanBoard device is an attractive way to digitize, organize, and display photos. 
     FIG. 14 is a flow chart of a method  200  of the present invention. The method  200  starts at an operation  202  when the server receives a request from an authorized client to modify a shared document. The server then carries out the request by modifying the shared document in an operation  204 . After the server modifies the shared document, it is updated, and the server notifies all authorized clients of the change in an operation  206 . The method  200  repeats itself until it is determined in an operation  208  that there are no more requests to process and the method  200  ends. 
     While this invention has been described in terms of several preferred embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. 
     The above discussion focused on the use of tokens and token detection spaces for initiating access to the group boards. However, a variety of input detection spaces useful for accessing boards are contemplated. For example, an IDU could be equipped with an array of electromechanical buttons each associated with a particular group. These buttons would preferably have a decal or some other visual indication of the nature of the associated group. Additionally, a feedback mechanism like an LED or such could indicate whether the associated group had been modified since it was last displayed on the IDU. 
     Another suitable input detection space could be formed from a pressure, touch, or stylus sensitive input device. Such a device could implement button-like operation or even digital inking. In the case of digital inking, the user could write in the desired board group and a handwriting recognition engine could determine the identity of the requested board group. Additional input detection spaces can be formed using voice recognition technology for entering group identifiers vocally. Of course, standard data entry technology such as keyboard and keypads would be suitable for manually entering group identifiers. 
     Those skilled in the art will appreciate that the client-server communications protocol adhered to could be selected from a variety available depending upon the desired system behavior. In one model, for example, the server could contact and update every client IDUs each time a change is made to the shared persistent space. In another model, each client IDU calls in with changes and is simultaneously updated by the server if necessary. Yet another model imposes periodic polling by the server (or client) which would result in content on both the polled client and the server being made consistent. 
     It is therefore intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention.