Abstract: A presence server architecture includes a central presence information database to store presence information about a multiplicity of publishing entities, and at least two presence servers to separately access and update said presence information. The present invention also includes a presence server which includes a means to access a central database storing presence information segments about each user from multiple publishing entities over time, an aggregator to aggregate said presence information segments about one user into a current presence information document, and means to detect if another presence server has recently modified presence information document about the user.

Abstract: A messaging system with reduced overhead, the system including a messaging server operative to receive a typing message sent from the first computer and destined for a second computer, and a message filter operative to determine a level of unused resources of the server, and instruct the server to forward the typing message to the second computer only if the level is within predefined parameters.