Tagg the Builder saysFormatting tags add meaning and emphasis: <strong>, <em>, <mark>, <small>, <del>, <ins>, and friends.
HTML has semantic formatting elements that carry meaning, not just looks. <strong> means importance (renders bold), <em> means emphasis (renders italic), <mark> highlights, <del> shows deleted text, <ins> inserted.
There are also pure-visual tags <b> and <i> — use the semantic ones when the meaning matters, since screen readers can announce them differently and search engines weigh them.
Power-ups you unlock
<strong> = important (bold) · <em> = emphasis (italic)
<mark> highlights · <del>/<ins> show edits · <small> fine print
<sub>/<sup> for subscript/superscript
Prefer semantic tags over plain <b>/<i> when meaning matters
The Unclosed Tag attacks — common mistakes
Using <b>/<i> for meaning when <strong>/<em> is more correct
Wrapping whole paragraphs in <strong> — emphasis loses force
Using <mark> as a generic highlighter instead of for relevance
Boss battleWrite a sentence that uses <strong>, <em>, and <mark> once each, then add a chemical formula with <sub> and an exponent with <sup>.
Example code
<!doctype html>
<html><head><meta charset="utf-8"></head>
<body>
<p><strong>Important.</strong> A bit of <em>emphasis</em>, some <mark>highlight</mark>,
a <del>mistake</del> <ins>correction</ins>, and H<sub>2</sub>O with E=mc<sup>2</sup>.</p>
</body></html>