Why it was huge?
The iPad was really the first of its kind. While tablet and touch screen technology existed, Steve Jobs's answer to those "in-between devices" — that is, bigger and more powerful than a phone, smaller and more mobile than a computer — gave the world a new way to think about the ways in which we consume media, play games, and communicate with others.
Plus . . .
As soon as the device was announced, companies immediately began releasing accessories, from simple cases to Apple's official line, featuring a keyboard and docking station. Soon, more innovative and creative accessories started to emerge, like lap desks, designer clutches, and recently, the world's most expensive case.
The iPad has a huge future in publishing, as evidenced first by the iBookstore, and then by the amount of magazines releasing apps for use specifically on the iPad. Now, with news of iPad-only subscriptions starting to emerge (and the technology allowing you to subscribe to a publication on the iPad), the iPad will likely take on a larger role in digital content delivery. And since just yesterday, news leaked of a second-generation iPad case sporting rear camera and SD card support, perhaps the rumors of an April 2011 launch are true.