Faceted navigation
Faceted navigation combines filters — size, price, colour — and mechanically generates an explosive number of URL combinations. Without guardrails, it floods the crawl with near-identical pages that dilute authority.
In practice
The right approach is decided by demand: a searched combination ('women’s trail running shoes') deserves a properly worked indexable URL; incidental cross-combinations go to noindex or behind neutralised parameters. This is the canonical example where closing pages gains more than opening new ones.