.Mac sync services are currently unavailable. Changes made to synced information will be reflected when the problem is resolved. All other .Mac services are unaffected. Last Updated: 04/05/06
The timing suggests either something in 10.4.6 put the hurt on Apple’s servers because of extra communication or in order to hide syncing problems with the software, they disabled the servers until they could push a fix. In either case, this is more downtime and isn’t going to instill enough confidence to trust Sync Services for anything mission critical.