Here are some links that you might find useful. This list will be added to frequently; major additions will be announced on the home page under News.
A markup language is a way of telling a program – often a web browser, but sometimes a formatting or typesetting program – how you want your text laid out and decorated. Writing plain text with markup lets you concentrate on your writing, using conventions like asterisks for boldface and underscores for italics, and let the computer worry about how to make it look good. Marking up your text this way also lets you make web pages, printed paper, and even books (both e-books and typeset) from a single document.
Markdown is the markup language used on GitHub, and in Jekyll sites generally (including this one). Largely thanks to GitHub it’s becoming ubiquitous. In addition to being fast and easy to write, some markdown processors let you embed blocks of code, colored according to syntax.
HTML Cheat Sheet - The best interactive cheat
Best one I’ve seen, anyway. HTML is the markup language of the web, and although it looks intimidating most people can learn it quickly. It’s available as an option on many blogging sites.
A good text editor can be used for more than just programming. It will have syntax coloring and keyboard shortcuts for whatever markup language you’re writing in, for example. It will also be open source, maintained and often extended by a large, helpful community.
GNU Emacs is my favorite text editor, period. When you start it for the first time it will show you a tutorial, and all of its documentation is built in. It’s been around for decades, and has acquired more extensions than Atom has color themes.