FYI, to get a monospace font, you have to wrap the entire thing in a <pre>. However, when displayed, line feed characters (\n) are converted to "\n<br>\n", which turns into three blank lines in a pre. So when editing, you need to make sure you use <br> and never any real \n's.
To start a line with spaces, you have to use " " when editing. You should also convert all double spaces " " to "  " if you want them to be displayed nicely.
That's how I lined things up in my profile.
The idea is that you select the PGP signed text, and then paste it into "gpg --verify". This works fine in Firefox and Chrome, but when you copy the data in IE, the clipboard version contains no \n chars. If I could have used <span> instead of <pre> this problem wouldn't have manifested. The profile editor wouldn't let me do that though.
I wish "copy" behaviour was consistant across browsers, when copying from a web page.