HTML and CSS
HTML (Hyper Text Markup Language) is the predominate language of the Internet.
Understanding the basic language of the Internet, you are more easily able to create your own web presence.
What do I mean by this?
Well as an internet marketer it basically means you can create or easily edit your own lead capture, sales and splash pages to promote products or services in safelists and traffic exchanges.
If you resell products you need to know how to edit the sales page in order to add your name and the price to it for example.
At a more advanced level you would be able to create, edit and maintain your own website pages. Not everyone wants to go this far, just remember that the possibility exists.
If you are interested in learning HTML or CSS (Cascading Style Sheets) and don’t mind a bit of reading, I suggest you visit Beginner’s Guide To HTML