Patent Publication Number: US-10778763-B2

Title: Content item sharing and synchronization system with team shared folders

Description:
PRIORITY CLAIM 
     This application claims the benefit under 35 U.S.C. § 120 as a continuation of application Ser. No. 15/242,144, filed on Aug. 19, 2016; which is a continuation of Ser. No. 13/891,042, filed on May 9, 2013, now U.S. Pat. No. 9,426,216, issued on Aug. 23, 2016; which claims the benefit under 35 U.S.C. 119(e) of provisional application 61/775,658, filed on Mar. 10, 2013. The entire contents of each of the above-mentioned applications is hereby incorporated by reference for all purposes as if fully set forth herein. The applicants hereby rescind any disclaimer of claim scope in the parent applications or the prosecution history thereof and advise the USPTO that the claims in this application may be broader than any claim in the parent applications. 
    
    
     COPYRIGHT STATEMENT 
     A portion of this disclosure of this patent document may contain material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     TECHNICAL FIELD 
     The present invention relates generally to sharing digital content and, more specifically, to sharing digital content using team shared folders. 
     BACKGROUND 
     Historically, users in an organization shared digital content with other users in the organization by hand carrying or otherwise transporting portable physical media such as floppy disks between computers. In recent years, however, data networks that interconnect computers allow users to send digital content to each other without having to transport physical media. For example, a user can send a file to another user as an attachment to an e-mail message. The digital content could include files, documents, audio, video, images, and other types of digital content. 
     Today, in addition to historical methods, users share digital content by making it available for access on network file servers. Generally, a network file server (or just “file server”) is a computer attached to a network providing a central location for shared storage of digital content. Typically, users create, update, modify, and delete shared digital content at the file server from their computer workstations which are also attached to the same network. 
     For example, a director of a sales department may create a file folder for containing pertinent sales team documents on the shared storage of a company file server for access by members of her sales team. Unfortunately, the sales director may not be able to provide access to the folder to her team members without coordinating with the company IT administrator, who in many organizations is overburdened and overworked. This is because in many organizations only the IT administrator is authorized to change access permissions associated with shared digital content on file servers. 
     A related problem is that a file server folder may be created with default permissions that are too permissive. For example, the file server folder created by the sales director may have default permissions that allow all employees in the company to access the folder which may not be desired by the sales director. Again, because of company policy, the sales director may have to coordinate with the IT administrator to restrict access to the folder to only her sales team, which can be a frustrating and time-consuming process. 
     Yet another problem with using network file server folders for sharing content is that users may not have access to the folders when the file server is unavailable or blocked (e.g., when users attempt to access the file server from outside the company network firewall), thereby making the users less productive in disconnected network environments. 
     What is needed is a solution for sharing digital content within a team of users. The solution should reduce administrative steps necessary to grant and revoke team member access to shared digital content. The solution should also facilitate access to shared content in disconnected network environments. The present invention provides a solution for these and other needs. 
     SUMMARY OF SOME EMBODIMENTS 
     A content item sharing and synchronization system providing team shared folders is disclosed and described. The appended set of claims provides a summary of some embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a very general block diagram of a computer system in which software-implemented processes of the present invention may be embodied. 
         FIG. 2  is a block diagram illustrating a networked computing environment that includes a content item sharing and synchronization system in accordance with some embodiments of the present invention. 
         FIG. 3  is a flow diagram illustrating a method for creating a team according to some embodiments of the present invention. 
         FIG. 4  is a flow diagram illustrating a method for accepting an invitation to join a team according to some embodiments of the present invention. 
         FIG. 5  is a flow diagram illustrating a method for deactivating the team shared folder of a team according to some embodiments of the present invention. 
         FIG. 6  is a flow diagram illustrating a method for activating the team shared folder of a team according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Introduction 
     Referring to the figures, exemplary embodiments of the invention will now be described. The following description will focus on a presently preferred embodiment of the present invention, which implemented in desktop, mobile, and/or server software operating an Internet-connected environment running under an operating system, such as the Microsoft Windows operating system. The present invention, however, is not limited to any one particular application or any particular environment. Instead, those skilled in the art will find that the system and methods of the present invention may be advantageously embodied on a variety of different platforms, including Linux, UNIX, Mac OS X, and the like. Therefore, the description of the exemplary embodiments that follows is for purposes of illustration and not limitation. The exemplary embodiments are primarily described with reference to block diagrams or flowcharts. As to the flowcharts, each block within the flowchart represents both a method step and an apparatus element for performing the method step. Depending on the implementation, the corresponding apparatus element may be configured in hardware, software, firmware, or combinations thereof. 
     Computer-Based Implementation 
     The computer-implemented techniques of the present invention may be implemented by one or more special-purpose computing devices. The special-purpose computing devices may be hard-wired to perform the techniques, or may include digital electronic devices such as one or more application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs) that are persistently programmed to perform the techniques, or may include one or more general purpose hardware processors programmed to perform the techniques pursuant to program instructions in firmware, memory, other storage, or a combination. Such special-purpose computing devices may also combine custom hard-wired logic, ASICs, or FPGAs with custom programming to accomplish the techniques. The special-purpose computing devices may be desktop computer system, server computer systems, portable computer systems, handheld electronic devices, networking devices or any other computing device that incorporates hard-wired and/or program logic to implement the techniques. 
     For example,  FIG. 1  is a block diagram that illustrates a computer system  100  upon which an embodiment of the invention can be implemented. Computer system  100  includes a bus  102  or other communication mechanism for communicating information, and a hardware processor  104  coupled with bus  102  for processing information. Hardware processor  104  can be, for example, a general-purpose microprocessor. Although only one hardware processor  104  is shown in  FIG. 1 , computer system  100  can have more than one hardware processor  104  coupled to bus  102  for processing information. 
     Computer system  100  also includes a main memory  106 , such as a random-access memory (RAM) or other dynamic storage device, coupled to bus  102  for storing information and instructions to be executed by processor  104 . Main memory  106  also can be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor  104 . Such instructions, when stored in non-transitory storage media accessible to processor  104 , render computer system  100  into a special-purpose machine that is customized to perform the operations specified in the instructions. 
     Computer system  100  further includes a read only memory (ROM)  108  or other static storage device coupled to bus  102  for storing static information and instructions for processor  104 . A storage device  110 , such as a magnetic disk or optical disk, is provided and coupled to bus  102  for storing information and instructions. 
     Computer system  100  can be coupled via bus  102  to a display  112 , such as a liquid crystal display (LCD), for displaying information to a computer user. An input device  114 , including alphanumeric and other keys, is coupled to bus  102  for communicating information and command selections to processor  104 . Another type of user input device is cursor control  116 , such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor  104  and for controlling cursor movement on display  112 . This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. 
     A touch-sensitive surface can overlay display  112  as an input device  114  to form a touch-sensitive display that provides an input interface and an output interface between the system  100  and a user. The touch-sensitive surface can be a sensor or set of sensors that accepts input from the user based on haptic and/or tactile contact. Contact with the touch-sensitive surface can be made by the user with a stylus or set of styluses or a finger or a set of fingers. The touch-sensitive surface can detect contact and any movement or breaking thereof using any of a plurality of touch sensing techniques now known or later developed including, but not limited to, capacitive, resistive, infrared, and acoustic wave techniques, as well as other proximity sensor arrays or other elements for detecting one or more points of contact, movement of contact, and breaking of contact with the touch-sensitive surface. 
     Although display  112 , input device  114 , and cursor control  116  are illustrated outside the dashed box representing computer system  100  in  FIG. 1 , it should be understood that one or more of display  112 , input device  114 , and cursor control  116  can be part of the form factor of the computer system  100 . For that matter, although main memory  106 , ROM  108 , storage device  110 , bus  102 , processor  104 , and communication interface  118  are illustrated inside the dashed box representing computer system  100 , it should be understood that one or more of these components can be external to the form factor of the computer system  100  and operatively coupled to the form factor through a peripheral interface. 
     Computer system  100  can implement the techniques described herein using customized hard-wired logic, one or more ASICs or FPGAs, firmware and/or program logic which, in combination with the computer system, causes or programs computer system  100  to be a special-purpose machine. According to one embodiment, the techniques herein are performed by computer system  100  in response to processor  104  executing one or more sequences of one or more instructions contained in main memory  106 . Such instructions can be read into main memory  106  from another storage medium, such as storage device  110 . Execution of the sequences of instructions contained in main memory  106  causes processor  104  to perform the process steps described herein. In alternative embodiments, hard-wired circuitry can be used in place of or in combination with software instructions. 
     The term “storage media” as used herein refers to any non-transitory media that store data and/or instructions that cause a machine to operation in a specific fashion. Such storage media can comprise non-volatile media and/or volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device  110 . Volatile media includes dynamic memory, such as main memory  106 . Common forms of storage media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, NVRAM, any other memory chip or cartridge. 
     Storage media is distinct from but can be used in conjunction with transmission media. Transmission media participates in transferring information between storage media. For example, transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus  102 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications. 
     Various forms of media can be involved in carrying one or more sequences of one or more instructions to processor  104  for execution. For example, the instructions can initially be carried on a magnetic disk or solid-state drive of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system  100  can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal and appropriate circuitry can place the data on bus  102 . Bus  102  carries the data to main memory  106 , from which processor  104  retrieves and executes the instructions. The instructions received by main memory  106  can optionally be stored on storage device  110  either before or after execution by processor  104 . 
     Computer system  100  also includes a communication interface  118  coupled to bus  102 . Communication interface  118  provides a two-way data communication coupling to a network link  120  that is connected to a local network  122 . For example, communication interface  118  can be an integrated service digital network (ISDN) card, cable modem, satellite modem, or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface  118  can be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links can also be implemented. In any such implementation, communication interface  118  sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. 
     Network link  120  typically provides data communication through one or more networks to other data devices. For example, network link  120  can provide a connection through local network  122  to a host computer  124  or to data equipment operated by an Internet Service Provider (ISP)  126 . ISP  126  in turn provides data communication services through the world wide packet data communication network now commonly referred to as the “Internet”  128 . Local network  122  and Internet  128  both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link  120  and through communication interface  118 , which carry the digital data to and from computer system  100 , are example forms of transmission media. 
     Computer system  100  can send messages and receive data, including program code, through the network(s), network link  120  and communication interface  118 . In the Internet example, a server  130  might transmit a requested code for an application program through Internet  128 , ISP  126 , local network  122  and communication interface  118 . 
     The received code can be executed by processor  104  as it is received, and/or stored in storage device  110 , or other non-volatile storage for later execution. 
     The above-described computer hardware is presented for purposes of illustrating the basic underlying desktop, mobile, and server computer components that can be employed for implementing the present invention. For purposes of discussion, the following description will present example in which it will be assume that there exists a “server” (e.g., a web server, capable of hosting methods of the present invention as web services) that communicates with one or more “clients” (e.g., desktop, mobile, and portable computers, from which users log on to the server in order to use the web services). The present invention, however, is not limited to any particular environment or device configuration. In particular, a client/server distinction is not necessary to the invention, but is simply a suggested framework for implementing the present invention. Instead, the present invention can be implemented in any type of system architecture or processing environment capable of supporting the methodologies of the present invention presented in detail below, including implementing the methodologies on a standalone computer (i.e., where users log on to the same computer that the computer-implemented methodologies are implemented). Additionally, the following description will focus on content item hosting service providers (e.g., Dropbox, Inc. of San Francisco, Calif., which provides cloud storage, file or folder synchronization, and client software to users) in order to simply the discussion. However, those skilled in the art will appreciate that the system and methodologies of the present invention can be advantageously provided by different types of service providers. 
     Overview of Team Shared Folders 
     Classically, shared file system folders have been centralized, such as on a network file server or a network attached storage device. Typically, administrators gave access to such folders by adding users to access control lists associated with the folders. If the administrator forgot to add a user to the access control list, the user didn&#39;t have access to the folder. Similarly, if the administrator forgot to remove a user from the access control list, the user had access to the folder after access was no longer authorized. Further, if the network to the file server was down or the file server was otherwise inaccessible, users did not have access to the folder. 
     In accordance with the present invention, a team shared folder is introduced. Users have access to the team shared folder simply by being a member of the team. A team account manager of the team can grant access to the team shared folder simply by inviting selected users to the team. Similarly, the team account manager can revoke access to the team shared folder simply by removing a user from the team. Unlike typical network file server folders, separate access control list management for the team shared folder apart from user team membership management is not needed to grant and revoke access to the team shared folder, thereby reducing administrative steps necessary to effectively manage access to the team shared folder. 
     In accordance with another aspect of the present invention, the team shared folder is stored at a server and synchronized with copies of the team shared folder on linked client computing devices of team members. Since the linked computing devices have copies of the team shared folder, the team members can access the team shared folder contents even when network access to the server is unavailable. 
     In one usage scenario, after the team account manager invites a user to the team and the user accepts the invitation, the current contents of the team shared folder at the server are automatically synchronized with the new user&#39;s computing device. This automatic synchronization creates a copy of the team shared folder and its contents at the new user&#39;s computing device which can be accessed by the new user even when network access to the server is unavailable. 
     In another usage scenario, after the team account manager removes a user from the team, the copies of the team shared folder at the removed user&#39;s linked computing devices are automatically deleted. This automatic deletion prevents the removed user having access to the team shared folder after the user is no longer a member of the team. 
     The architecture and operation of an example content item sharing and synchronization system implementing team shared folders will now be described in further detail. 
     Networked Computing Environment 
       FIG. 2  is a block diagram illustrating networked computing environment  200  that includes content item sharing and synchronization (CISS) system  210  in accordance with some embodiments of the present invention. Environment  200  includes different types of users  212  viewed from the perspective of CISS system  210 . 
     User Accounts 
     Users  212  can have accounts with the CISS system  210 . CISS system  210  can store user account information in an account database (not shown). User accounts can be associated with credential information. Credential information is any information CISS system  210  can use to authenticate users  212 . Non-limiting examples of credential information include username and password information and digital cryptographic certificate information. Users  212  can authenticate with CISS system  210  by presenting valid credential information. For example, a user can authenticate with CISS system  210  by presenting a valid username and password associated with an account. 
     Authenticated Sessions 
     When a user  212  successfully authenticates with CISS system  210  by presenting valid credential information, CISS system  210  establishes an authenticated session for the user  212 . The authenticated session allows the user  212  to interact with the CISS system  210  over a period of time without requiring the user  212  to present valid credential information for each interaction. CISS system  210  can establish an authenticated session using a wide variety of mechanisms depending on the requirements of the implementation at hand and the present invention is not limited to any particular manner for establishing the authenticated session. 
     In some embodiments, CISS system  210  establishes authenticated sessions by sending a small piece of data to the users&#39;  212  client computing devices  214  that is stored at the client computing devices  214 . This small piece of data is sometimes referred to as a “cookie” or “browser cookie”. Each cookie can contain information that uniquely identifies the authenticated session to which the cookie pertains. Cookies can be included in network requests  220  and network responses  222  sent between client computing devices  214  and CISS system  210 . CISS system  210  can use the authenticated session information in the cookies to identify the users  212  making the network requests  220 . While browser cookies are used in some embodiments to establish authenticated sessions for users  212 , other mechanisms can be used in other embodiments. For example, an alternative to using browser cookies could include CISS system  210  embedding authenticated session information in uniform resource locators (URLs) of web pages served by CISS system  210  to client computing devices  214  in network responses  222 . 
     User Interaction 
     Users  212  interact with CISS system  210  in the context of an authenticated session. User interaction can involve users  212  sending network requests  220  to CISS system  210  from their client computing devices  214 . User  212  interaction also involve users  212  receiving network responses  222  at their client computing devices  214  from CISS system  210  in response to the network requests  220 . 
     Users  212  can cause network requests  220  using one or more different types of client applications (not shown) executing on client computing devices  214 . Users  212  can receive network responses  222  also at the client applications. Typically, network requests  220  will be caused by users  212  interfacing with graphical user interfaces (GUIs) presented to users  212  by the client applications at client computing devices  214 . Such interfacing can include, but is not limited to, entering text into a text form field and activating a GUI element (e.g., a button, a menu, checkbox, etc.) using a pointing device (e.g., a mouse) or a touch-gesture on a touch-screen display. Typically, network responses  222  contain presentation information that can be used by the client applications to render and display the GUIs. In some embodiments, the different types of client applications include standard web browsing software (e.g., INTERNET EXPLORER, CHROME, FIREFOX, OPERA, SAFARI, or the like), mobile web applications, and dedicated “thick-client” software applications. In some embodiments, network requests  220  and network responses  222  are formatted in accordance with the Hyper Text Transfer Protocol (HTTP) or the Secure-Hyper Text Transfer Protocol (HTTPS). In some embodiments, the presentation information is formatted in accordance with the HyperText Markup Language (HTML) and the JAVASCRIPT programming language. However, it should be understood that network requests  220 , network responses  222 , and presentation information can be formatted in a wide variety of different ways according to the requirements of the particular implementation at hand and the present invention is not limited to any particular formatting scheme. 
     Content Items 
     User accounts stored at CISS system  210  can be associated with a set of content items also stored at CISS system  210 . Content items can include, but are not limited to, files and folders. A file can be any named logical collection of data. Files can include, but are not limited to, digital documents (e.g., .DOC, .PDF, .XLS, .TXT, and other document file types), digital audio files (e.g., .WAV, .M4A, .MP3, .AAC, and other digital audio file types), digital video files (e.g., .AVI, .MOV, .MP4, and other video file types) and digital image file (e.g., JPEG, .TIFF, GIF, PNG, and other image file types). A folder is a named logical collection of one or more files and/or one or more folders. A content item that is associated with only one user account can be considered private to that account. A content item that is associated with more than one user account can be considered shared between the accounts. 
     CISS system  210  can support version history with respect to content items stored at CISS system  210 . The version history can also be stored in the form a content item journal similar to a file system journal, for example. The version history can allow users  212  to recover previously deleted content items from the version history. Similarly, the version history can allow users  212  to restore previous versions of content items that have been edited. The version history for a content item can be a sliding window (e.g., the past 30 days) or since the content item was created. 
     Teams 
     A user account can belong to a “team” of accounts. A team is a set of one or more user accounts. For example, a business may have a “sales” team, a “marketing” team, a “finance” team, etc. A user account that belongs to a team is referred to herein as a “team account”. At least one team account of a team is for a team account manager. The team account manager has special privileges with respect to the team. In particular, the team account manager can invite other users to the team, can remove users from the team, can activate the team shared folder, and deactivate the team shared folder. These operations that can be performed by the team account manager are described in greater detail below. 
     Users  212 , including team account managers, that authenticate with a team account associated with a team are referred to herein as “team members” of the team. Users  212  that authenticate with an account not associated with the team are referred to herein as “non-team members” with respect to that team. For example, in  FIG. 2  some users  212  are shown as being members of team “Alpha” while others users  212  are shown as being non-team members with respect to team “Alpha”. Further, while only one team, namely team “Alpha”, is shown in  FIG. 2 , it should be understood that CISS system  210  can support more than one team (e.g., hundreds or thousands or more teams). Further, a non-team member with respect to a team can be a member of one or more other teams. For example, non-team members  212  shown in  FIG. 2  that are not members of team “Alpha” may each be members of one or more other teams. Similarly, a team member of a particular team can be also be a member of one or more other teams, including teams that non-team members of the particular team are members of Thus, the terms “team member” and “non-team member” as used herein are relative to a particular team. 
     Linked Client Computing Devices 
     Users  212  use client computing devices  214  to interact with CSS system  210 . Client computing devices  214  can include mobile computing devices, stationary computing devices, and portable computing devices. Mobile computing devices  214  can include mobile phones and smart phones. Mobile computing devices  214  can be configured with a mobile operating system such as ANDROID, BLACKBERRY, IOS, S40, WINDOWS PHONE, WINDOWS 8, WINDOWS RT, or the like. Stationary computing devices  214  can include desktop computers, workstation computers, and server computers. Stationary computing devices  214  can be configured with a desktop or server operating system such as WINDOWS, MAX OS X, UNIX, LINUX, FREEBSD, and the like. Stationary computing devices  214  can also include set-top computing devices such as gaming consoles, digital media players, or other set-top computing devices operatively coupled to a television. Portable computing devices  214  include tablet computers and laptop computers. Tablet computers can be configured with a mobile operating system such as one of the mobile operating systems listed above or a desktop or server operating system such as one of the desktop or server operating systems listed above. Laptop computers can be configured with a desktop or server operating system such as one of the desktop or server operating systems listed above. 
     When a user  212  successfully authenticates with an account from a client computing device  214 , CSS system  210  can “link” the client computing device  214  to the account. A link between a client computing device  214  and an account can be based on a unique device identifier of the client computing device  214 . For example, CSS system  210  can link a client computing device  214  and an account by storing an association between the account and the device&#39;s identifier in the account database. A user  212  can link multiple of his or her client computing devices  214  to the same account by successfully authenticating with the account from each of the multiple devices  214 . 
     Content Item Client Synchronization Agents 
     A client synchronization agent (not shown) can be installed on each of a user&#39;s  212  linked client computing devices  214 . The client synchronization agent installed on a linked client computing device  214  is configured to communicate and interoperate with CSS system  210  to keep the contents of a client-side content item repository stored at the linked client computing device  214  synchronized with the set of content items associated with an account. Thus, the client-side content item repository can also be considered to be associated with the account. For the purpose of providing clear examples, the client-side content item repository stored at a client computing device  214  and associated with an account is referred to hereinafter as a “client repository” and the set of content items associated with the account stored at CSS system  210  is referred to hereinafter as a “server repository”. While the term “repository” is used in both references, it should be understood that a client repository can take a different form than a server repository. For example, a client repository can be a collection of file system files and folders stored and managed by the operating system file system of the client computing device at which the client repository is stored. In contrast, the server repository may be stored in a distributed file system on one or more server computing devices. 
     To synchronize a client repository with a server repository, the client synchronization agent can send  224  and receive  226  synchronization data to and from CSS system  210 . The synchronization data can be formatted according to an application-level networking protocol such as HTTP or HTTPS. The synchronization agent can run continuously on the client computer device  214  and can send  224  and receive  226  the synchronization data automatically without requiring user  212  interaction. 
     The synchronization agent and CSS system  210  implement a synchronization protocol for keeping the client repository on which the synchronization agent is installed synchronized with the server repository. A wide variety of synchronization protocols may be used depending on the requirements of the implementation at hand and the present invention is not limited to any particular synchronization protocol. For example, the synchronization protocol can be based on delta encoding techniques so that only portions of content items that are changed are sent  224  and received  226  over the data network. 
     In some embodiments of the synchronization protocol, after a client repository is changed, the synchronization agent sends  224  the change to CSS system  210  to be applied to the server repository. The change can include adding a content item to the client repository, modifying a content item in the client repository, or deleting a content item in the client repository. In some embodiments, multiple changes to the client repository are sent  224  to CSS system  210  in a batch to reduce network communications. 
     Cross-Device Synchronization 
     As discussed above, a user  212  can have multiple devices  214  linked to an account. Each of those linked devices can have a synchronization agent installed and a client repository. In some embodiments of the synchronization protocol, changes made to one of the client repositories are synchronized to the other client repositories through the server repository. In particular, the cross-device synchronization can involve the device  214  with the changed client repository sending  224  the change to CSS system  210  which applies the change to the server repository. After applying the change to the server repository, the CSS system  210  then sends  226  the change to the synchronization agents on each of the user&#39;s  212  other linked devices  214  to be applied to the other client repositories. In this way, a change to a client repository at one of the user&#39;s linked devices  214  is replicated to the client repositories of the other of the user&#39;s linked devices  214 . 
     Cross-User Synchronization 
     As discussed above, a content item can be private to one account or shared among multiple accounts. In some embodiments of the synchronization protocol, when a content item is private to an account, changes to the content item are synchronized only among the devices  214  linked to the account. For example, a private job performance review folder associated with an account may be synchronized only among a user&#39;s  212  laptop computer  214  and the user&#39;s  212  workstation computer  214 . A shared content item, on the other hand, can be synchronized among all devices  214  linked to all of the accounts the content item is shared amongst. For example, a shared sales team folder may be synchronized among all devices  214  linked to all user accounts that the sales team folder is shared with. 
     Conflict Resolution 
     In some embodiments of the synchronization protocol, if the same shared content item is changed in two different client repositories of two different devices  214  at the same time, CSS system  210  does not attempt to merge the changes when received  224 . Instead, CSS system  210  separately saves the conflicting changes in two versions of the shared content item. One version contains the changes to the shared content item received  224  from one of the devices  214  and the other version contains the changes to the shared content item received  224  from the other device  214 . 
     While in some embodiments conflicts are not merged, it should be understood that CSS system  210  could automatically merge conflicts according to a heuristic or a set of heuristics, which may be user-configurable. 
     Team Shared Folders 
     A team shared folder is a special shared content item folder associated with a team. The team shared folder can contain contents in the form one or more shared files and/or one or more shared folders. Thus, the team shared folder can be arranged in a file/folder hierarchy with the team shared folder being the root folder of the file/folder hierarchy. 
     The team shared folder has at least two states: active and inactive. When active, the team shared folder and all of its contents are shared with all team members. When inactive, the team shared folder and all of its contents are shared with only team members that are team account managers of the team. Further, when inactive, the team shared for and all of its contents are removed from all linked computing devices of all team members that are not team account managers. When active, the team shared folder and all of its contents are synchronized with the client repositories on all linked computing devices of all team members. 
     When synchronized to a client repository of a team member&#39;s linked computing device, the team shared folder can correspond to an operating system file system folder. The team shared folder contents correspond to operating system file system files and folders contained in the operating system file system folder corresponding to the team shared folder. 
     Creating a Team 
       FIG. 3  is a flow diagram illustrating a method for creating a team according to some embodiments of the present invention. Such a method can be performed by one or more computing devices. For example, one or more steps of the example method shown can be performed by CISS system  210 . Although steps are depicted in  FIG. 3  as being performed in a certain order, some steps can be performed in a different order than depicted and/or performed concurrently with other steps. 
     In block  302 , a request to create a team is received from a user  212 . Receiving the request can involve receiving one or more network requests  220  from a client computing device  214  used by the user  212 . 
     The request to create the team can be received in at least two different contexts. In one context, the request to create the team is received as part of a request to create a new account with CISS system  210 . In another context, the request to create the team is received as part of a request to convert an existing account of the user  212  to a team account. In both contexts, the resulting account is a team account of the user  212  and associated with the new team. 
     The request to create the team account can include information provided by the user for creating the team account. The user  212  can provide the information through a graphical user interface presented at the user&#39;s  212  client computing device  214 . Such information can include a name for the team such as, for example, “Sales Team”. Such information can also include a specification of one or more other users  212  to invite to the team. For example, the specification can be in the form of e-mail addresses, usernames, or other account identifiers of the one or more invitees. Further, such information can include a specification of whether the team shared folder is active or inactive. 
     In block  304 , CISS system  210  creates the team by storing metadata in a database or datastore. The stored metadata can include or be based on information provided by the user  212  creating the team. For example, the stored metadata can include the team name, identifiers of the one or more invitees, and the specification of whether the team shared folder is active or inactive. Creating the team can also include storing metadata that indicates that the account of the user  212  who created the team is a team account manager account of the team. Creating the team can also include creating the team shared folder in the server repository for the team. 
     In block  306 , CISS system  210  sends notifications or causes notifications to be sent to the specified invitees. For example, CISS system  210  may send e-mail messages and/or text messages to the specified invitees. The notifications can indicate that the invitee has been invited to join a team, the team name, and the user  212  who created the team. The notifications can also include a hyperlink (URL) which, when activated by the invitee, conveys the invitee&#39;s acceptance of the invitation to join the team. Alternatively, the hyperlink can take the invitee to a web page of CISS system  210  that allows the invitee to convey acceptance. If the invitee does not wish to be a member of the team, the invitee can ignore the notification. 
     In block  308 , CISS system  210  synchronizes the team shared folder of the team and its current contents from the server repository to the client computing device  214  of the user  212  that created the team. This synchronization can include sending  226  synchronization data representing the team shared folder created and its current contents in the server repository for the team at block  304 . The result of this synchronization is that the client repository at the client computing device  214  of the user  212  that created the team has a copy of the team shared folder and its current contents. The user  212  can now add files and folders to the team shared folder in the client repository and those files and folders will be synchronized back to CISS system  210  for storage in the server repository for the team. 
     Accepting an Invitation to Join a Team 
       FIG. 4  is a flow diagram illustrating a method for accepting an invitation to join a team according to some embodiments of the present invention. Such a method can be performed by one or more computing devices. For example, one or more steps of the example method shown can be performed by CISS system  210 . Although steps are depicted in  FIG. 4  as being performed in a certain order, some steps can be performed in a different order than depicted and/or performed concurrently with other steps. 
     At block  402 , CISS system  210  receives a request from an invitee to join a team for which the invitee received an invitation for. For example, receiving the request to join the team can include CISS system  210  receiving one or more network requests  220  from a client computing device  214  of the invitee. The request to join the team can be made by the invitee in the context of an existing non-team account of the invitee, which case the invitee&#39;s existing account is converted to a team account of the team. Alternatively, the request to join the team can be made by the invitee in the context of creating a new account which will also be a team account of the team for the invitee. 
     At block  404 , CISS system  210  joins the invitee&#39;s account to the team. This account can be an existing account of the invitee or a newly created account of the invitee as described in the preceding paragraph. Joining the invitee&#39;s account to the team as a team account can also include linking the invitee&#39;s client computing device  214  from which the request to join the team was sent. 
     At block  406 , CISS system  210  determines whether the team shared folder of the team is active. If active, then, at block  408 , CISS system  210  synchronizes the team shared folder of the team and its current contents from the server repository for the team to the linked client computing device  214  of the invitee  212  that accepted the invitation to join the team. This synchronization can include sending  226  synchronization data representing the team shared folder and its current content in the server repository for the team to the linked client computing device  214  of the invitee  212  that accepted the invitation to join the team. The result of this synchronization is that the client repository at the client computing device  214  of the invitee  212  that accepted the invitation to join the team has a copy of the team shared folder and its current contents at the linked client computing device  214 . 
     If, at block  406 , CISS system  210  determines that the team shared folder of the team is not active, then, at block  410 , CISS system  210  determines not to synchronize the team shared folder of the team to the linked client computing device  214  of the invitee  212 . However, even if the team shared folder is not active, the invitee&#39;s account is still joined to the team as a team account. 
     Deactivating the Team Shared Folder 
       FIG. 5  is a flow diagram illustrating a method for deactivating the team shared folder of a team according to some embodiments of the present invention. Such a method can be performed by one or more computing devices. For example, one or more steps of the example method shown can be performed by CISS system  210 . Although steps are depicted in  FIG. 5  as being performed in a certain order, some steps can be performed in a different order than depicted and/or performed concurrently with other steps. 
     A block  502 , a request to deactivate the team shared folder of a team is received by CISS system  210  from a team account manager of the team when the team shared folder is active. Receiving the request can involve receiving one or more network requests  220  from a linked client computing device  214  of the team account manager. 
     At block  504 , CISS system  210  causes the copies of the team shared folder in the client repositories of the linked client computing devices  214  of team members  212  that are not team account managers to be removed from the client repositories. This removal can involve CISS system  210  sending  226  synchronization data to the linked client computer of the team members  212  that are not team account managers to remove the team shared folder from the client repositories. Even though the team shared folder is removed from the client repositories, the server repository is retained (i.e., is not deleted). Further, the team shared folder is not removed from the client repositories of the linked client computing devices  214  of the team account managers  212 . By not removing the team shared folder from the server repository of the team or from the client repositories of the linked client computing devices  214  of the team account managers  212 , the team shared folder can continue to be modified and synchronized among the linked client computing devices  214  of the team account managers  212 . 
     Activating the Team Shared Folder 
       FIG. 6  is a flow diagram illustrating a method for activating the team shared folder of a team according to some embodiments of the present invention. Such a method can be performed by one or more computing devices. For example, one or more steps of the example method shown can be performed by CISS system  210 . Although steps are depicted in  FIG. 6  as being performed in a certain order, some steps can be performed in a different order than depicted and/or performed concurrently with other steps. 
     At block  602 , a request to activate the team shared folder of a team is received by CISS system  210  from a team account manager of the team when the team shared folder is inactive. Receiving the request can involve receiving one or more network requests  220  from a linked client computing device  214  of the team account manager. 
     At block  604 , CISS system  210  synchronizes the team shared folder and its current contents from the server repository for the team to at least the client repositories of the linked client computing devices  214  of team members  212  that are not team account managers. This synchronization can involve CISS system  210  sending  226  synchronization data to at least the linked client computing devices of the team members  212  that are not team account managers. The result of this synchronization is that at least the client repositories at the client computing devices  214  of the team members  212  that are not team account managers have a copy of the team shared folder and its current contents at the linked client computing devices  214 . 
     While the invention is described in some detail with specific reference to a single-preferred embodiment and certain alternatives, there is no intent to limit the invention to that particular embodiment or those specific alternatives. For instance, those skilled in the art will appreciate that modifications may be made to the preferred embodiment without departing from the teachings of the present invention. Further, the sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction.