(Mashable) -- Apple developers, start your engines. Mac users, start dreaming of how much cooler your desktop or laptop experience could be this summer. That's when Apple will launch the latest big cat-themed Mac OS X, version 10.8: Mountain Lion. At 8:30 a.m. EST Thursday, the developer preview version of Mountain Lion became available to Apple's legions of app makers. Mashable was briefed on the new Mac OS prior to the announcement. Bottom line? It's a few more vital steps closer to fully connecting the experience you have on the Mac with the world of the iPad and the iPhone -- dumping iChat in favor of iMessage and Twitter, to take the most radical example. It's almost as if it makes your Mac moonlight as an iPad.
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Apple: Latest Mac operating system, named Mountain Lion, will launch this summer
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30 percent of Mac users have OS 10.7 installed, another 50 percent favor Snow Leopard
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Developers will continue to make two separate versions of apps they want on Mac and iOS
Take a quick gander at a video we put together with material from @placeholder, then a gallery of screenshots -- and last but not least, your chance to chat up a storm about this major Mac development in the comments.