Sorry Jeff,
You really need to listen to the advice you got from the majority in the last topic (i.e., that it is your assumptions about users and markdown that is the problem, and not the users themselves).
Just to use SU as an example, even when the preview box is above the ‘fold’, it starts out as nothing more than a dotted rectangle that is one character high. It isn’t labelled ‘preview’ or any similar indication it just sits there by itself. Even when I, who do know about markdown, and the features of the formatting icons above the text box, am typing a message, I’m not paying attention to anything but what I’m typing. Even if I were to notice the results in the unlablelled ‘preview’ box, there is nothing to indicate that what is shown is what will be posted, until after the post is submitted. For all the average user might know, assuming they pay any attention to it at all, it’s just a box of crap.
Also, the formatting instructions in the right pane of the page are terse and abbreviated to the point of uselessness.
Even if a user were to read it and try it out (for example, the first one, ‘put returns between paragraphs’), they may very well (legitimately) believe that a single return will have a visible result on the posting (the instructions don’t say anything about how many returns to use, and in this context, the term being plural doesn’t convey any useful information). Even though you have a link to something identified as a ‘Full Reference’, you haven’t given the user any real reason to go there. The instructions that are shown might as well be written in cuneiform, as far as most users are concerned, so why would they feel the need to go to the full reference?
You can latch onto the idea of ‘user myopia’ and ‘the fold’ all you want, since it apparently makes you feel better about your design decisions, but the clear and unalterable fact is that YOU DID IT WRONG!
Yes, user myopia exists. An intelligent designer will compensate for that myopia in the design of the system, rather than trying to force the user to not be myopic.
The default behavior should be to display exactly what is entered in the text box. Add explicit formatting as applied.
From a programming perspective, doing that is much simpler than trying to convince every user to do it your way. Simply put, you’ll get much better, and more consistent results from accepting and working with ‘user myopia’ than you ever will from trying to fight it.