The MessagePad's unique selling point was its ability to capture handwriting onto its touch-sensitive screen using a stylus - which some fans dubbed 'the carpenter's knife'.

The MessagePad 110 box
Apple's handwriting recognition technology was called Calligrapher. While quite advanced for its time, it was frequently lampooned by the media for its constant inability to recognise handwriting, especially in cursive form.
Even The Simpsons got in on the joke, sketching out a scene where a MessagePad was used to store the memo "Beat up Martin", but which was interpreted as "Eat up Martha". The Doonesbury comic strip also poked fun at the MessagePad's iffy handwriting recognition as well, much to the annoyance of Apple.
In an everyday setting, the MessagePad was seen as a pretty cutting edge device, though. For example, the user could write "Dinner with Laura tomorrow" onto its screen and then tap on the Assist button, which would - depending on Newton's interpretation of the text - open a meeting slip already completed and showing the last-accessed person named Laura, tomorrow's date and the time allocated to the meeting.
The MessagePad had its rivals, of course. Perhaps the most notable was the Palm Pilot, which used a different, character-by-character text recognition technology that, although more difficult to learn, proved to be more accurate at recognising user's input.
The MessagePad lampooned by Gary Trudeau
Amazingly, a Gary Trudeau cartoon was incorporated as an Easter Egg into Newton OS 2.0.
The MessagePad was still hugely successful for Apple though, with around seven models of the handset developed between 1993 and 1998, together with several different versions of the Newton OS as well, from 1.0 to 2.1.
The Newton OS had many strings to its bow, including fax and email capabilities. The Notes application allowed users to store information such as memos, checklists or to-do lists. Although initially fairly basic, Newton OS 2.0 was refined to allow users to bullet-point notes and develop "trees" - a string of related memos.

Newton licensed: Sharp's ExpertPad
Names was developed for storing contact details. A nice feature, present even on most basic mobile phones today, was that Newton would automatically make the entry of a birthday a recurring event, ensuring you never had an excuse to forget that gift.
COMMENTS
Still using my 2100
And I will continue to use it until someone comes out with a PDA that can match it in usefulness.
Successful Innovation requires as many as possible new forms
Successful innovation needs as many as possible new forms of a device to come to the fore, as often as possible. The Japanese have an inbuilt advantage with innovation, their reluctance to let any single idea or form of a product sit for very long in the manufacturing stage.
The faster you let new thinking make an input and the smaller your manufacturing run, the better you can meet market perceptions with new variations of the same product.
We saw the opposite here in the UK with a fixation on trying to get the maximum length of product run for the minimum product development cost. By the time the business can see that the market is fed up with the currect product, it is too late. Some other innovator has stolen your market from right under your nose. Ergo, we lost cameras, pocket calculators, you name it.
Never try and control your market by any other means than fresh innovation of the product and always test your market by constantly revising the product to suite new perceptions.
Don't forget the eMate
There was a weird Newton-based machine built that's eerily similar to the OLPC: the Newton eMate. It had a keyboard and a little LCD, ran Newton OS, and was cool.
Title
"those using the MessagePad as a compliment to a PC"
As in "hi, PC, you're looking great today!", is it? :O)
J
Yes, there were PDAs before Newton, alright . . .
@Ben
Yes, there were. I know -- I still have a couple of the ones I had stuffed in a drawer somewhere. I do also have my MP2000 which I use everyday in my business and a brand new 2100 waiting in the wings for the 2000 to die. I'm not sure if you actually used some of these early PDAs by Sharpe and Casio, but the ones I started with and ditched were unbelievably awful. The Psion was closer to acceptable, but in the end it was really a scaled down laptop, much akin to the Windows CE efforts, albeit much better than WinCE.
The Newton, on the other hand was an integrated device that was created with pen computing in mind at every turn. A real treat to use (as I still do). It's funny to think how those awful early PDA interfaces drove the folks at Apple to come up with something more intuitive -- that is the same drive behind the iPhone. Boom? or Bust? Only time will tell -- meanwhile -- everyday my MP2000 soldiers on!
