Abstract: The performance of a network system having one or more requester nodes, one or more provider nodes, and one or more intermediate nodes is improved by determining the digital signature of a received file, looking up the digital signature in an index of signatures, and forwarding a previously compressed version of the requested file when the digital signature is found in the index of signatures.

Abstract: A real time notification system that tracks, for each user, the logon status of selected co-users of an on-line or network system and displays that information in real time to the tracking user in a unique graphical interface. The invention provides user definable on-line co-user lists, or “buddy lists”, that track specific co-users in real-time automatically. A user can create many separate buddy lists of co-users, either with intersecting or disjoint lists of users, and label these buddy lists according to the user's preference. The user can update a buddy list or create new buddy lists whenever necessary. When a user logs on to a system, the user's set of buddy lists is presented to the buddy list system. The buddy list system attempts to match co-users currently logged into the system with the entries on the user's buddy list. Any matches are displayed to the user. As co-users logon and logoff, a user's buddy list is updated to reflect these changes.

Abstract: Electronic messages may be processed using a stamp authority by receiving an electronic message, identifying a stamp associated the message, determining if the stamp is valid, and, if the stamp is determined to be valid, distinguishing the message from messages with which a valid stamp is not identified.

Abstract: Personalizing communications for a first communication platform includes accessing status information for communication sessions by a communication identity that leverage a first communication platform other than an instant messaging platform. A participant list associated with the communication identity and the first communication platform is passively configured to persistently reflect a list of participant identities from communication sessions in which the communication identity recently participated using the communication platform.

Abstract: Embodiments of multicast messaging systems and methods are disclosed for facilitating the multicasting of messages and/or other content to a group of users such that users may send messages to a group. One embodiment includes a method of transmitting multicast messages, including receiving a first multicast message and an indication of a first message group from a first sending user, identifying a first set of recipients related to the first message group, and transmitting the first message to the identified recipients. Another embodiment includes a computer system configured to receive a multicast message designating a group and then to communicate the multicast message to intended recipients.

Abstract: A real time notification system that tracks, for each user, the logon status of selected co-users of an on-line or network system and displays that information in real time to the tracking user in a unique graphical interface. The invention provides user definable on-line co-user lists, or “buddy lists”, that track specific co-users in real-time automatically. A user can create many separate buddy lists of co-users, either with intersecting or disjoint lists of users, and label these buddy lists according to the user's preference. The user can update a buddy list or create new buddy lists whenever necessary. When a user logs on to a system, the user's set of buddy lists is presented to the buddy list system. The buddy list system attempts to match co-users currently logged into the system with the entries on the user's buddy list. Any matches are displayed to the user. As co-users logon and logoff, a user's buddy list is updated to reflect these changes.

Abstract: Transferring instant messaging sessions includes receiving a selection, from a user within a user interface, of at least one instant messaging session from among multiple instant messaging sessions to transfer from a first instant messaging controller on a first device to at least a second instant messaging controller on a second device, where the user is signed on concurrently to the first instant messaging controller on the first device and the second instant messaging controller on the second device. At least a portion of the selected instant messaging session is transferred from the first instant messaging controller on the first device to the second instant messaging controller on the second device and the transferred portion of the instant messaging session is made perceivable on the second instant messaging controller on the second device.

Abstract: Transferring instant messaging sessions includes receiving a selection, from a user within a user interface, of at least one instant messaging session from among multiple instant messaging sessions to transfer from a first instant messaging controller on a first device to at least a second instant messaging controller on a second device, where the user is signed on concurrently to the first instant messaging controller on the first device and the second instant messaging controller on the second device. At least a portion of the selected instant messaging session is transferred from the first instant messaging controller on the first device to the second instant messaging controller on the second device and the transferred portion of the instant messaging session is made perceivable on the second instant messaging controller on the second device.

Abstract: Announcing new users of an electronic communications system includes receiving an indication of a new user of an electronic communications system. The new user has an identifier for the electronic communications system. Existing users of the electronic communications system that are known to the new user are identified. The identified existing users are sent a message notifying the identified existing users of the identifier of the new user. The identified existing users may be enabled to add the identifier of the new user to participant lists used by the identified existing users. The new user may be enabled to add identifiers of the identified existing users to a participant list of the electronic communications system used by the new user.

Abstract: Detecting a physical location change of a mobile communications device may initiate a process to initiate, or cancel, forwarding of future incoming communications to the mobile communications device. Forwarding information for a mobile communications device may be accessed and modified using an interface that communicates using an Internet Protocol network.

Abstract: A messaging application user interface has an input element for receiving electronic messages and an output element for displaying electronic messages. The messaging application user interface can be implemented so as to maintain a subset of the plurality of potential message recipients, the subset being determined using a predetermined criterion. The messaging application user interface also can be implemented so as to auto-complete a partially entered address based on the subset of potential message recipients. A set of user-selectable signals that modify auto-completion behavior also can be used with the messaging application user interface. The messaging application user interface can be used in an instant messaging system to allow a user to send instant messages to and exchange comments with a plurality of other users without having to switch among several instant message windows.

Abstract: Techniques are described for forwarding an instant message addressed to an intended instant message recipient to the recipient's mobile telephone. Techniques are also described for prohibiting the forwarding of an instant message addressed to an intended message recipient to the recipient's mobile telephone. Further techniques are provided for updating an intended message recipient's on-line presence information (and/or reflecting the same) to indicate that the intended message recipient prohibits message forwarding to the potential message recipient's mobile telephone or to indicate that the intended message recipient's mobile telephone is unavailable to receive a communication.

Abstract: Transferring instant messaging sessions includes receiving a selection, from a user within a user interface, of at least one instant messaging session from among multiple instant messaging sessions to transfer from a first instant messaging controller on a first device to at least a second instant messaging controller on a second device, where the user is signed on concurrently to the first instant messaging controller on the first device and the second instant messaging controller on the second device. At least a portion of the selected instant messaging session is transferred from the first instant messaging controller on the first device to the second instant messaging controller on the second device and the transferred portion of the instant messaging session is made perceivable on the second instant messaging controller on the second device.

Abstract: Techniques are described for forwarding an instant message addressed to an intended instant messaging recipient to the recipient's mobile telephone when the recipient's mobile telephone number is known to the instant message sender. In one example, an instant message is forwarded to the intended recipient's mobile telephone number when the instant message sender's contact information for the intended recipient includes an instant message address (e.g., a screen name or other type of instant message identifier) and a mobile telephone number, without dependence upon the intended recipient's presence on the instant message (IM) system or through actual login or registration with an IM forwarding service. In a more particular example, an address book of the instant message sender includes an entry for the intended recipient where the entry includes an instant message address and a mobile telephone number of the intended recipient.

Abstract: Detecting a physical location change of a mobile communications device may initiate a process to initiate, or cancel, forwarding of future incoming communications to the mobile communications device. Forwarding information for a mobile communications device may be accessed and modified using an interface that communicates using an Internet Protocol network.

Abstract: Social network information may be shared across online service providers. Thus, one online service provider M that maintains a membership separate from a second online service provider N may nevertheless use the social network maintained by the second online service provider N to tailor content and/or services based on such social network information.

Abstract: Passively populating a list of participants of an electronic communications system includes maintaining a participant list of users of an electronic communications system to be used by a user of the electronic communications system. Existing users of the electronic communications system that are known to the user are identified, and communications strengths between the user and each of the identified existing users are determined. The identified existing users with the highest communications strengths are designated for addition to the participant list. An existing group or a newly created group within the participant list to which each of the designated users should be added may be identified.

Abstract: Organizing a participant list includes maintaining a participant list of users of an electronic communications system to be used by a first user of the electronic communications system. Communications strengths between the first user and each of the users included in the participant list are determined. The users included in the participant list are organized based on the corresponding communications strengths. Communications strengths may be determined for users included in a group within the participant list, and the users within the group may be organized within the group based on communications strength. An additional group in the participant list in which some or all of the users included in the participant list are organized based on communications strength may be provided.

Abstract: Systems and techniques for transferring electronic data between users of a communications system include a host system structured and arranged to receive and deliver messages of various types between users of the communications system. The host system includes an instant messaging network; a mail gateway; and a configuring network in communication with both the instant messaging network and the mail gateway. The instant messaging network enables instant messaging communication between users of the communications system and has the capability to monitor whether a certain user is capable of receiving an instant message at a particular moment. The mail gateway receives and delivers e-mail messages to users of the communications system. The configuring network is dedicated to automatically configuring instant messaging communication between an intended recipient of an e-mail message and the sender of the e-mail message.

Abstract: A sender's degrees of separation from a recipient may be used to aid in spam filtering or to otherwise handle a communication. The “degrees of separation” represent a metric used to quantify whether/how the recipient is linked to the sender through intermediary people or other entities. For example, a recipient may know a first user (first degree of separation) and the first user may know a second user (second degree of separation) who knows the sender of an e-mail. In this case, the sender is separated from the recipient by two degrees of separation (by two other contacts). A level of “trust” or “legitimacy” about a sender's communication can be inferred by looking at whether the sender is linked to an intended recipient. Typically, user contact lists (e.g., address book, buddy list, and/or white list) are evaluated to determine the number of degrees (or hops) are required to link or relate two users.