wysiwyg = What You See Is What You Get. Meaning you don't enter any kind of code, but you rather just see what you are doing. Want to make a text bold, press the corresponding button and the marked text appears bold. If you don't use a wysiwyg editor you would see something like [bold]My Bold Text[/bold]. The term wysiwyg is mainly used in the HTML world.

Markup languages

HTML is a markup language. You are marking your text with statements about how the text should be displayed. There are though other markup languages:

• TeX (or Latex)
  All studens probably know what one, as it has strong academic roots. Very well for formulas and other scientific stuff.
• XML
  Probably everybody has been in touch with XML. XHTML is a form of XML <mytag>Hello World</mytag>
• GML
  Sorry, don't know that one. Seems to be an ancestor of HTML and TeX.
• HTML
  We all know that one.
• BBcode
  Mostly used in forums, where one don't want to use a wysiwyg editor (for whatever reason) but also want to give users the possibility to "style" their posts. They look like [italic]here is my stuff[/italic] that.

To most of these markup languages there's also a corresponding wysiwyg editor.

HTML
It's easy and there's plenty of such wysiwyg editors: Microsoft Word, Dreamweaver, Amaya, Golive (not sold anymore), Microsoft Expression, NVU. There's actually a nice list on Smashing Magazine.

XML
Don't have much experience, but just look at the google search results.

TeX
I've been working with MiKTeX and LyX.

GML & BBcode
Don't know of any editor for that.

Pros and Cons of wysiwyg

Pros	Cons
Very easy to learn and use. User sees directly what he gets.	You don't have full control. You are dependant on your editor.
Wysiwyg editor might have automation integrated	HTML: For SEO reasons, your editor might now always produce the best HTML code (advantages of clean content markup)
Syntax erros are not possible	Options provided by the editor might mislead the user to do ugly things.

I love wysiwyg editors. In fact, I wrote this article using a Wysiwyg editor, but in this same article here, the editor didn't provide me with the option of writing a table. So I could either find some configuration option for wordpress or just go ahead and quickly write the HTML myself (which I did). It's always good to know the underlying technic, but then in the daily work, I'm too lazy to write all the markup myself.

Using a wysiwyg editor is like drawing with a given pattern. You can never fully express your creativity.

And to all you students out their: Writing a diploma thesis on Word can be a pain (at least on version < 2003). Latex is so much nicer!