Tag soup

Tag soup is the pejorative name for HTML documents that are technically malformed — improperly nested tags, unclosed elements, obsolete attributes — yet still render correctly in a browser because browsers were engineered to be forgiving rather than strict. This forgiveness was not a bug but a strategic choice: it allowed the web to grow faster than standards could be enforced, democratizing publishing at the cost of semantic precision. The tag soup era (roughly 1995–2005) produced billions of documents that look correct to humans but convey almost no structural meaning to machines, creating the epistemic sludge that search engines and accessibility tools still struggle to parse. The transition to Web standards was an attempt to drain this swamp, but the swamp had already become the ecosystem.