While you can argue if today's update to Mac's software is a compelling upgrade, you have to applaud Apple for regularly releasing steady updates to its system. It stands in stark contrast to Microsoft, which struggled for five years to release its latest version of Windows. And that update seems no more compelling than what Apple offers every couple of years.
The secret, Apple execs say, is that Mac developers don't have to spend near the resources on the core of its operating system. Those guts are based on an open source version of Unix, meaning volunteers and companies around the world work to keep it modern and safe. Apple does, too, and releases those updates for the Unix community to share.
What Apple doesn't share is the special look and feel that it layers over the Unix core. Those beautiful touches give the Mac its unique appearance and experience. Apple also doesn't share the applications that it writes, such as iPhoto and Garage Band, that add to the Mac's allure.
Open source is perhaps best known these days for Linux, also a Unix-like system that is shared freely among volunteers and companies. Linux advocates want to challenge Microsoft, sometimes sounding as if theirs is a holy war based on a communal, almost socialist endeavor. Apple, in contrast, has quietly exploited another communal effort to build one of the most profitable companies in tech.