All Online Apple Stores across the entire world have officially gone down. This can only mean that they want no spoilers for the upcoming announcements for the new Apple Product(s). In my opinion, this can only mean that the stores are going under maintenance to be ready for the overflow of sales from the announcement today.
Currently, the Online Stores are back up, but who knows how long that may last. Nothing new on the site though, so they will probably go down again to put the new product's page up.