Game Center is coming to Mountain Lion when it debuts next month (you can get a bit more info on Apple’s “What’s New” Web page). This is a really big deal for gamers, because for the first time in Apple’s history, the company is providing its users with a social networking framework for games.

This vacuum has long been filled by a patchwork of third-party services. GameRanger is a practical example – a game finding and chat service that predates Mac OS X, and is still going strong (thanks at least in part to its expansion into the much bigger PC gaming market). Valve’s Steam service offers much of this functionality. Blizzard has its Battle.net service, which has become increasingly important to the company not just for game finding, ladders and rankings, but also for digital distribution and Digital Rights Management (DRM) technology. There are many others as well.

Now Mountain Lion is taking a page from iOS with Game Center, Apple’s own framework for social networking in games – game ladders and rankings, achievement tracking, friend finding, and game matching. What’s more, the software provides cross-platform functionality – so if you’re an iOS user with an existing Game Center account, you’ll be able to continue on with your Mac. But more than that, you’ll be able to challenge iOS gamers from your Mac, as well.

This means that Game Center on the Mac won’t be starting from square one, as Game Center for iOS did. Mountain Lion users are going to be gaining access to an already populated ecosystem. And hopefully it’ll give game developers who already have a leg up on iOS an added incentive to bring more of their titles to the Mac. We’ve already seen that trend, especially with Apple’s introduction of the Mac App Store – I anticipate it will be bolstered with Game Center’s availability on the Mac platform as well.

I don’t expect that Game Center is a death knell for any of the existing Mac game matching services. For one thing, Game Center is relegated to Mountain Lion. So it’s hands off for the many Mac users that can’t or won’t upgrade to the new OS when it debuts in July. That also means it’s fundamentally useless for legacy games, which many Mac users still play – games that either can’t be refit with the new technology or whose developers and publishers don’t really have an incentive to make Mountain Lion ready.

Of course, some companies have a vested interest in supporting their own systems (like Valve’s Steam service and Blizzard’s Battle.net). So they may be slow to update their games with support for Game Center, if they add it at all.

Ultimately, I don’t think Mac users will ever achieve parity with their PC gamer counterparts in terms of quantity of games, prices or release dates. Avid gaming enthusiasts are probably always going to be lured to the Windows platform because of Microsoft’s long-standing support for game technology and the enormous ecosystem of PC-centric developers and publishers.

But that matters less and less with each passing month. In ways big and small, Apple is gradually developing ways of its own to make Mac gaming a more user-friendly, fun experience. Game Center is the latest example, and it’s one I’m really looking forward to using when Mountain Lion debuts.