[Turing_Machine]

Markdown requires far less typing than HTML for common use cases.

    *This is italic.*
    <i>This is italic.</i>

or (semantic version):

    <em>This is italic.</em>

The second has three times the markup overhead as the first and the third has four times the markup overhead. That matters. If you're writing long-form text it matters a lot.

[Turing_Machine]

Paragraphs are even worse. In Markdown you just hit return. In HTML you have to write <p></p> or <p />. That really adds up for a long piece.