Apple is serious about this whole mobile thing. The next version of its Mac OS X operating system for desktops and laptops, "Mountain Lion," offers a variety of features that first made an appearance in iOS, including Game Center (for competing against one’s friends) and iCloud, which syncs user data across a variety of Apple devices. This evolution should come as no surprise to anyone who regularly follows Apple: Over the course of the past few years, the company has placed increasing emphasis on its mobile endeavors, with many of the initiatives pioneered there eventually finding their way into the PC realm. Mac OS X Lion, for example, offered up an App Store clearly molded after the one present for some time on iOS devices. Apple claims Mac OS X Mountain Lion will arrive this summer. If that proves the case, it will be some months ahead of its next big opponent, Microsoft’s Windows 8. As with Mountain Lion, Windows 8 also embraces mobile-centric features: In addition to a "start" screen of colorful tiles linked to applications (the better for operating on tablets), it will include an app store and under-the-hood tweaks meant to optimize battery life and wireless connectivity. By the end of 2012, the battle between the two longtime rivals will have entered a wholly new stage. – …