It was cheaper and smaller, and it came without a monitor or keyboard so that Apple could price it at $499.
The Mac mini came at the peak of Apple's long attempt — somewhat futile at the time — to "switch" people from Windows PCs to Macs.
Part of the idea, as Apple touted it at the time, was that this stripped down computer would make it easier for people to get hooked on OS X and Apple's iLife suite.
Did it work? Well, Apple never killed the Mac mini, so it certainly hasn't been a failure. But it wasn't the thing that sparked Apple's big market share gains, either.
Contrast that with the iPod nano. Introduced later in 2005, this was a different kind of gamble for Apple.
The nano was a smaller, more fashionable iPod with less storage, starting at $200. The nano wasn't a stripped down iPod, it was a bet that people valued fashion and portability more than raw storage. It worked: The nano became the most popular iPod in Apple's lineup, paving the way for every thin, flash-memory-based gadget that followed.
So, the likely gamble with an mini iPad? That customers will value portability and fashion more than raw screen size and resolution. (Read More: Apple's Smaller iPad Risks Cannibalization: Strategist )
Apple executive Eddy Cue might have put it best: "I found email, books, Facebook and video to be very compelling" on a 7-inch tablet, he told other Apple executives in an email nearly two years ago. "Web browsing is definitely the weakest point, but still usable."
If greater portability and content consumption are what people really crave, a mini iPad could turn out to be a bigger hit than the original — like the iPod nano was. But if consumers actually crave a big canvas, a mini iPad could turn out to have a smaller impact.