Abstract: A method for content-based presence communication entails receiving presence information, storing the presence information in any arbitrary data format, validating a subscription request to subscribe to the presence information by determining if information contained within the subscription request represents an authorized subscription relationship, and communicating the presence information when the presence information matches the subscription expression.

Abstract: A method, performed by a registrar of a presence service, for registering a user with a presence service. The method entails negotiating a key with a client device operated by the user in order to establish an encrypted communications channel between the client device and the registrar via a proxy node, authenticating the user by exchanging messages through the encrypted communications channel and through a separate e-mail channel, binding a universally unique identifier identifying the user with one particular function node that is interposed between the proxy node and a publish-subscribe subsystem of the presence service and creating a user profile for the user and storing the user profile in a persistent data store.

Abstract: A method, performed by a registrar of a presence service, for registering a user with a presence service. The method entails negotiating a key with a client device operated by the user in order to establish an encrypted communications channel between the client device and the registrar via a proxy node, authenticating the user by exchanging messages through the encrypted communications channel and through a separate e-mail channel, binding a universally unique identifier identifying the user with one particular function node that is interposed between the proxy node and a publish-subscribe subsystem of the presence service and creating a user profile for the user and storing the user profile in a persistent data store.

Abstract: A method for managing a subscription to content-based presence information entails receiving a subscription-suspension message from a device at a presence service, identifying the subscription associated with the subscription-suspension message, suspending the subscription, and sending a response from the presence service to the device to notify the device that the subscription has been suspended. Suspending the subscription may involve accumulating notifications in a persistent data store. The method may further involve receiving a subscription-resumption message at the presence service to resume the subscription that was suspended.

Abstract: A method, performed by a registrar of a presence service, for registering a user with a presence service. The method entails negotiating a key with a client device operated by the user in order to establish an encrypted communications channel between the client device and the registrar via a proxy node, authenticating the user by exchanging messages through the encrypted communications channel and through a separate e-mail channel, binding a universally unique identifier identifying the user with one particular function node that is interposed between the proxy node and a publish-subscribe subsystem of the presence service and creating a user profile for the user and storing the user profile in a persistent data store.

Abstract: A method of updating a virtual business card entails receiving the virtual business card, subscribing to an update service that notifies of updates made to the virtual business card, and receiving a notification that an update to the virtual business card has been published. By publishing updates, contacts who subscribe to the business card receive notifications whenever the business card is updated.

Abstract: A method for content-based presence communication entails receiving presence information, storing the presence information in any arbitrary data format, validating a subscription request to subscribe to the presence information by determining if information contained within the subscription request represents an authorized subscription relationship, and communicating the presence information when the presence information matches the subscription expression.

Abstract: A method for managing a subscription to content-based presence information entails receiving a subscription-suspension message from a device at a presence service, identifying the subscription associated with the subscription-suspension message, suspending the subscription, and sending a response from the presence service to the device to notify the device that the subscription has been suspended. Suspending the subscription may involve accumulating notifications in a persistent data store. The method may further involve receiving a subscription-resumption message at the presence service to resume the subscription that was suspended.