To accomplish the same thing in HTML would require
<h1> some text </h1>
not burdensome, but certainly not as easy as Markdown.
Online Markdown editors
Some of the most popular online markdown editors are as follows:
Markdown for research writing
Authorea is an online document editor that has full Markdown support. Researchers are using Markdown more and more for writing research papers and Authorea's support for Markdown means that anybody writing technical or scientific documents may incorporate as much Markdown as they want into their document.
Authorea also renders the online Markdown environment beautifully to HTML5 in the browser -- so documents are web-native and beautiful no matter what.