1. A method implemented by one or more computing devices of a service provider to implement a synchronization service, the method comprising: causing a provider module to monitor a history of application setting changes for a particular application and on a first computing device that is associated with a user of the synchronization service, the provider module being specified in configuration information associated with the particular application; and in response to identification by the provider module of a first change to application settings on the first computing device, converting application settings associated with the first change from a format used by the particular application, to a different format that enables synchronization via the synchronization service with at least one other computing device; and after said converting, adding the first change to a synchronization communication module and employing the synchronization communication module to communicate the first change to the at least one other computing device associated with the user for synchronization.