Returning back to universal sync mechanism idea posted almost a year ago Universal server storage and news about syncing Angry Birds saves, for the beginning it can be quite simple to organize one worldwide cloud service accessible from any OS and device where any application can store some data.

Example:
Application developer registers at superappstoragecloudservice.com and adds several applications.
Each application obtains its own GUID id and then implementation on any platform can access superappstoragecloudservice.com/appStorage// and store and retrieve settings, save files etc.
It's good idea to limit each app slot about small like 4 kilobytes per user not to allow content storage