Well for reddit comments, the vast majority of the comments I typically make will make use of quotes, bold, italics or lists (the comments that include markdown), I use stuff like tables quite infrequently. So even remembering a small subset of the markdown will make my comments much more readable. I learn the features I use regularly, from reading other comments, that's how I picked up markdown originally.

I'm learning Python, I don't expect to learn all the features, hopefully I will learn a small subset, enough to be dangerous!

> Well, why not a WYSIWYG editor (similar to that on Stack Overflow) that generates HTML?

Absolutely, this is a good solution also. I personally like knowing the markdown features, I guess, but that's just me ;-) There is an extremely similar feature in the RES addon which allows live preview, not possible on a smaller screen though. It even includes a helpful list of markdown features for the newbie.