I average 140wpm without any "advanced typing techniques", so I don't think they're really necessary. I can't speak to whether or not they would be helpful, though. I do think it's very worthwhile to be able to type this fast - people speak somewhere around 150wpm on average, and being able to type as fast as you speak is useful for instant messaging, etc.
That's a bit different. Court stenographers, along with the people who do real-time TV captions, use specialized chording keyboards (stenographs, they look like this [0]) that allow them to type words or even whole phrases with a single or just a few strokes. That's how they're fast - you can only go so far typing one letter at a time.
Right, I thought I had read you could actually enable some of the chording techniques on a standard keyboard at some time. Though, I don't recall the story. Quickly googling isn't showing too much.
Regardless, I know I could get faster than I am. I hover just over 80 to 90. To get a lot faster, I was always under the impression that I would need something like that. I have also always thought that I have no need for that. So it works out. :)
With n-key rollover, you can use Plover to mimic stenotype chording on typical qwerty. It's been posted/discussed here a few times, so that might be what you're thinking of.
I developed speed from text MUDs. I'm the type of person who dislikes customizing my setup and prefer to play straight; as a result, I had to consume, digest, and react to pretty large quantities of barely-differentiated text in tenths of a second.
At some point I just sat down and did some deliberate practice. I'm actually still not as good at typing as I would like to be, I have some glitches like only using my right thumb for the spacebar and sometimes using the wrong Shift key. There are a lot of programs out there that will help you do deliberate practice, it's just a matter of putting in some time.
