MobileUserSync allows administrators to backup a local Mac OS X 10.2+ machine to a remote server running the bundled rsync package. The bundled rsync version is 2.6.3 which has some valuable fixes and additions allowing hfs+ data to be written. The bundled version is built for Mac OS X.
MobileUserSync comes from the Mac OS X 10.3 Workgroup Manager capability to manage local machine users called Mobile Users. While the settings and passwords are managed the data is not. MobileUserSync adds this functionality.
While OS X 10.4 adds Mobile User Sync capability, the implementation is unknown at the time of this writing. MobileUserSync uses rsync which allows for granular include and exclude lists, this functionality is built into the initial installed version.