I think they are gearing up to make their own fixed-target hardware spec. They talked a lot recently about working with Intel on drivers. It wouldn't be a stretch for them to partner up with Asus or someone like that to make an Ivy-bridge or newer spec system that's mac mini sized to go under the tv. Remember their fabled big-screen mode? It all fits in my mind. Big screen+mini box+Linux.

Most security issues are circumvented by appropriate use of firewalls. Many vulnerabilities require phishing or similar attacks which are irrelevant on servers. Privilege separation limits any damage.

The simple fact is that it's much easier to just rebuild an infected or compromised laptop than re-tool your entire company to use Linux. Far, far cheaper, as you will already have someone in-house building new laptops anyway; the process is no different, just a few more man-hours.

Any sensibly-run company will use a mixture of technologies; Unix is strong on scalability and security, Windows for ease-of-implementation, off-the-shelf solutions and rapid development, mostly due to the widespread availability of cheap skills, and an out-of-the-box extensible directory service that makes user management a lot easier. Linux for web services, appliances and VM hosting.

There is no black and white solution to questions of this kind, but the argument against Linux is the same for any OS out of its comfort zone: cost.

They will probably save money compared to powering and cooling the equivalent disk array.

Or by online gamers do they include Silver members downloading something?