How does the HTML Editor work? How do I get plain text input?

Two related questions.

How does the HTML Editor work?

If you are creating items on the web (eg a discussion message or a knowledge entry), or you're replying, you get a text box with an HTML editor (like a word processor for Web pages)

One frustration with this is that when you want to reply to a discussion message, you seem to get caught in the original message, with a line on the left hand side,like this:

Hello there
How are you

There are a few ways of dealing with this:

1. If you want to reply at the beginning, on in the middle, go to the point you want to start, and click the "Decrease Indent Button" (1,2 on the chart below), and the blockquote should disappear

2. If you want to respond at the end, just go to the end of the message, and use the right arrow key.

Sometimes you will want to generate blockquotes (as I did above) or