- Browsing the web: if you have an iPad, you almost fully stop doing it on your desktop (especially now that iOS 6 and Google Chrome are out)
- Handheld console gaming
- Standalone console gaming (the iPad may not have come very far on that route, yet, but it is on its way, as this article, among others, suggests: http://www.theverge.com/2012/6/2…)
- Medical documentation and assessment, patient care (http://medcitynews.com/2011/11/5…)
- Interactive information displays: Museums use this a lot already: the iPad is being put into a case that locks the Home button, therefore only displaying the content that it should display; another good example is McDonald's using it as an info display/surf station in its fancier restaurants.
- Small/children's room television sets: Many people already use the iPad as a second (third, fourth) TV; something that people used an HTPC and a display or a standalone PC in a kid's room for before.
- Blogging/publishing/writing: I know a few people who have already adapted to the zero feedback of the keyboard of the iPad and are almost ten-fingers quick at typing their content.
- Textbooks/learning: From iBooks to proprietary apps, there are a lot of learning institutions encompassing the iPad into their learning/distribution of learning materials.
- Children's entertainment and learning: There are already thousands of edutainment apps for preschoolers out there.
- Consumer photo editing: Once the domain of simple Paint-like programs, then a mass adoption of basic Photoshop started, iPhoto took over and now it's iPhoto on the iPad. AI allows edits which were much too complex for beginners just a couple of years ago (even with great input devices) and consumers embrace it – without needing input devices.
- Social networking: Sounds almost a bit too obvious, but ask anyone who uses both Facebook and an iPad – they'll tell you that they almost never switch on their computers to do some Facebook.
- Note taking: As basic as it is, would we have believed if anyone would have told us seven years ago that in the near future we would not use a keyboard or a pencil anymore for taking notes? (Thanks, Evernote!)
- Document display: Before tablets, dedicated display/input systems were the only ones you could use to display a presentation or a PDF to someone at work. Now that that's changed, tablets are taking over.
- Information search: Very close to the browsing I wrote about above, it's obvious that many people are turning to apps when they look for information, rather than using a traditional PC with a browser – Wikipedia is a good example.
- Shopping online: Before Tablets (and smartphones), there was no other way to enter your information than to use a traditional display/input system. Today, eBay already makes about 10 billion dollars from mobile purchases (http://allthingsd.com/20120718/e…). One reason for this is that for an online shopping experience to satisfying, a beautiful and 'haptic' experience is way more important than fluent text input.
I could go on like this for ages, but maybe I am just a mobile enthusiast…(,
See the answer on Quora: