The rumour machine is abuzz with the prospect of Apple releasing a tablet, and there are a number of other people, most notably TechCrunch and Archos, have tablet systems either out or on the planning desk. It will be interesting to see if anyone can finally make one that is worth owning.
The first tablet PC I had used was a Compaq Concerto somewhere in the mid 90′s which was a 486 based tablet version of a standard Compaq notebook. I believe the much glorified Apple Newton preceded it, however while both these products were much hyped at the time but never delivered any real value and were cancelled without replacement.
In the 15 years or so since they first appeared tablets have made periodic returns, always for a brief flurry of enthusiasm that eventually came to nothing. The most sucessful itteration was the slight tangent into the PDA space. While that eventually was a dead end market as well, it did directly contribute to the creation of the smartphone market, which has been an increasingly bouyant tech market.
I am not confident that the track record of tablets gives great hope of success this time. There are a couple of new technologies that give this iteration a better chance. The first is multitouch touchscreens. This will make the platform more usable and increase the number of applications. The second is pageflow. While it is more an application of technology rather than a radically new technology, it does change the feel of scanning though multipage documents or lists of items, essentially making it a more natural feel.
The other positive aspect is the operating system options that exist now. A major problem previously was trying to use a full size operating system on a platform that needed to be lightwieght. A modified iPhone OS or Android platform could offer the functionality needed for the platform to operate while being lightweight enough to operate well on a less powerful platform and get good battery life.
I think this article in PCMag might have a good handle on what the Apple platform might end up looking like. One factor I definitely agree with is that new version of the tablet has to offer a different experience from a standard laptop, which needs to be more than just adding a different interface. There is also a good rundown of the tablet market in this NYTimes article.