Episode 5: Semantic HTML5, IA and Accessibility - So Many Missed Opportunities

Most developers who moved from table-based layouts to CSS-based layouts solved the visual problem and stopped there. They replaced tables with divs, controlled everything through CSS classes, and produced pages that looked exactly as intended in a browser and meant almost nothing to a machine. Semantic HTML5 exists to close that gap - and in 2018, almost nobody was using it properly.

Episode 5 of the #SEOisAEO series brought Jono Alderson, Kim Krause Berg, and Simon Cox together with Jason Barnard to examine a layer of the answer engine problem that most AEO discussions skipped: before structured data markup, before Knowledge Graph signals, before any of the credibility work, the machine has to be able to read the page. If the HTML structure doesn’t communicate what each piece of content is, the machine is guessing.

The argument Jono Alderson made here - and has made consistently since - is that semantic HTML is the foundation everything else rests on. An <article> tag tells the machine this is a standalone piece of content. An <aside> tag tells it this is supplementary, not primary. A <nav> tag tells it this is navigation, not content. A <main> tag identifies the primary content area. None of this is complicated. All of it is routinely ignored.

Kim Krause Berg brought in the accessibility dimension, which matters for AEO in a way that’s often missed. Screen readers and answer engines share a requirement: they both need content that’s structured for sequential comprehension without visual context. A page that works well for a screen reader - clear heading hierarchy, descriptive link text, meaningful element labelling - works well for an algorithm parsing it for answer-engine purposes. Accessibility and AEO aren’t parallel disciplines that occasionally overlap; they’re solving the same underlying problem from different directions.

Simon Cox’s contribution focused on information architecture: how the organisation of content across a site, not just within a single page, signals topical authority and entity coherence to a machine. A site with a clear, consistent IA tells the algorithm something about how the brand understands its own domain. A site with a fragmented, inconsistent structure suggests a brand that hasn’t thought carefully about what it is.

For the #SEOisAEO series, Episode 5 made the case that the technical foundations aren’t optional groundwork before the real AEO work starts. They are AEO work. An answer engine can’t recommend what it can’t read.

Watch here>>

Published by: Semrush. Host: Jason Barnard. Guests: Jono Alderson, Kim Krause Berg, Simon Cox. October 02, 2018