You won’t find free, demo, or trial software in the upcoming Mac App Store. Unlike the App Store on iOS devices, Apple insists that developers submit only paid apps for the inclusion on the Mac App Store.

The news reached us yesterday when Apple updated news section on its developer site. The company’s "submission tip" regarding third-party Mac apps reads as follows:

Do not submit demos, trials, or betas for Mac App Store Review. Your website is the best place to provide demos, trial versions, or betas of your software for customers to explore. The apps you submit to be reviewed for the Mac App Store should be fully functional, retail versions of your apps.

Another tip demands that Mac apps distributed through the Mac App Store write files in standard locations in order to "promote a more consistent user experience."

The decision to close the door to free and demo software is strange given that the App Store has allowed both paid and free apps from the onset, as well as re-downloads. It might have something to do with the fact that Mac apps are typically heavier than their iOS counterparts, resulting in a significant burden on the already overstretched iTunes servers. I’m also guessing Apple wants to simplify things and make the review process as smooth as possible.

Of course, Apple could easily allow free and trial software when the Mac App Store successfully takes off and the company beefs up its infrastructure when they flip the switch on its new billion-dollar datacenter facility in North Carolina, pictured above.

Apple’s boss Steve Jobs announced the Mac App Store at a media conference last month. It should do for the Mac what the App Store did for the iOS software – democratize development and distribution of third-party Mac apps. Although critics later speculated it’ll stifle innovation, pointing their finger at the App Store submission guidelines and widely publicized app rejections, Jobs clearly said at the presser that the Mac App Store won’t be the only place to buy apps. In addition, submissions to the Mac App Store adhere to a different, more relaxed set of guidelines than third-party iOS apps.