Hello.
Heres a screenshot of me editing the wikipedia:
http://zerror.com/unorganized/crap/nogoodenough.png
All the webmasters on this mail list will spot the problem with this text in 1 second: is unreadable. The space betwen lines, the lines length, the complexity of the text... Is really hard to read. A HTML textarea can server for writting emails, and simple text, but on this image fail short. Textareas are not designed for this, or are not good enough.
How a webmaster can make that text better? well.. you need to stop using the HTML textarea widget. And emulate it with divs, css and javascript. You need to colorize the code. Nowdays *ALL* good code editors colorize code. If our code editor don't colorize the wiki sintax, or don't even try, our editor is bad. I could be wrong, but maybe [[links]] and {{templates}} can be detected and colorized. And since you are emulating a editor, you can add a bit of usefull beaviors: make so some areas are read only, so the cursor skip then. Oh.. and you can make the whole think AJAXified,.. so wen you click [Edit section] this section become editable, and wen you "save", the edit view send, and is replaced by the result. Why would you want to people bounce here and there to post stuff in 2009?
He... our computers support 24 M colors, and we are showing text with 2 colors? pfff....