Actually, the system supports most HTML markup, so it's possible to stylize text if you know basic HTML. You can put text in <b>bold</b>,<i>italicize</i> it or even <u>underline</u> it. You can also:

1. create numbered lists
2. add funky colors
3. use the blink tag

...and do anything else HTML lets you do. To keep viewers safe we remove anything from the HTML that might be a security threat before saving it, including javascript, iframes and most flash (embedded Youtube videos are allowed). It's also not a great idea to use too much markup, since the lesson introduction is used in the PDF, and we strip out all of the HTML before putting it in.