Today at its Worldwide Developers Conference in San Francisco, Apple officially launched the next version of its desktop operating system. Mac OS X Mountain Lion, which the company first previewed in February, will be available for purchase next month. While the next iteration of any major operating system is always exciting news for the product's most devoted users, Mountain Lion represents something much bigger for Apple and its customers: It continues the company's slow convergence of its desktop and mobile platforms. This trend first became obvious with the release of Lion last summer.