With its introduction in 2002, the Apple Xserve was, according to Steve Jobs, the result of listening to their customer needs. This rack-mountable sever running OS X was going to lead Apple into server rooms and datacenters around the business world, and signaled Apple taking the enterprise computing customer seriously.
How much the world has changed in 8 years. With their subtle announcement that the Xserve was no more as of 1/31/11 (an availability statement on the website and a transition guide to move users to the mac Pro or Mac Mini), Apple removes any doubt that their focus, first and foremost, is on being a consumer products company. Not that there is anything wrong with that; they make wildly successful consumer products and playing to your strengths is always a good idea.
And before Apple loyalist start yelling about how good a server a Mac Pro or Mac Mini makes, they aren't enterprise server equipment. Period. They don't rack mount, use multiple power supplies, offer a lights-out management scheme, offer low-power consumption video and are not purpose designed servers. This stuff all matters in the enterprise computing world. No matter how much the pimp out a Mac Pro, it's still not a purpose built server.
I'm sure there are people who will use the Pro and Mini as departmental or special purpose servers. But the ability to work in the server role does not alone make for enterprise server equipment.
Of course, if the future of the corporate datacenter really is cloud computing, the backend hardware will rapidly become little more than a collection of commodity components, and it while it would appear that Apple was banking on that when they made the choice to end their Xserve product line the truth is that it was never a winner for Apple anyway. Apple presence in the datacenter is so minimal it doesn't even blip the radar, and this action by Apple is more significant in showing that Apple recognizes where their future lies rather than any real comment on Apple's vision of the datacenter future.