For Pussy:
HTML (Hypertext Markup Lannguage) is the coding which makes up every web page. (Click 'View.Source' to see what really makes up this page)
Mustardmit's post refers to the fact that some web forums allow contributors to type in the codes so that their text appears in colours, or underlined, or in italics, etc.
AB used to allow users to do this but, since AB was 'revamped', it's been disabled. The instructions for doing so are still on the tutorial page:
http://www.theanswerbank.co.uk/Info/Tutorial/
(under 'posting gudelines') but, unless anything in this post appears in <b>bold</b> or <i>italics</i>, they're not currently working.
Chris