As someone who's been in the 'server/hosting/networking' biz for a good few years, I can say that I cant see this being used for major user connectivity. Why? Let me explain.
Lets take Google - everyone knows it and its a prime example. Google are arguably the most visited site in the world. Because of this they have datacenters all over the place - the idea being that even if a bunch of the DC's went down for any reason (terrorists, fires, natural disasters, etc) they would be able to continue running with hardly any impact.
Lets say Apple uses this new datacenter for say, a free MobileMe service (e.g free diskspace), or a spotify type service.
What happens when the datacenter goes down (which it will - it happens all the time and is NOT something that can be avoided)? We all loose connectivity. It would be foolish to rely on one site to serve all those demands.
Which brings me to my second point. Having everyone connect to a single datacenter location is going to be a HUGE bottleneck. It would actually work out cheaper and much more reliable to have multiple smaller datacenters in various locations. If Apple are going to be hooking up just 1 DC they will need a hell of a lot of bandwidth, and they would have a big problem trying to get that from a lot of providers in the area.
My guess? Its a processing farm, providing processing power for encryptions, conversions, etc.