Content silo: A way of organising a site into separate topic sections whose pages link up and down within the section but rarely or never across to other sections.
The idea, and the debate
Siloing grew out of the idea that keeping links inside a topic concentrates ranking value and makes each section’s subject clearer to search engines. A strict silo on a pet site would let the dog-training posts link to each other and up to the dog-training hub, but never across to the cat-behaviour section, even where a post on multi-pet homes obviously needs both.
Google has not documented siloing as something it rewards, and the strict version is debated among SEOs. The milder version (organise content into clear sections and link heavily within them) is just good site architecture, and few people argue with that. The arguments start when silo rules stop you adding a link a reader would actually want.
Silos in WordPress
Most WordPress sites get a loose silo for free from categories: a category archive, URLs that may include the category slug, and breadcrumbs. What turns that into a strict silo is the linking policy in the content, not the settings. Watch for two side effects of strict siloing:
- Useful cross-topic posts end up with few links, or become orphans, because they don’t belong to one silo.
- Restructuring category URLs to “build silos” on an established site creates hundreds of redirects for a debatable gain.
What to do instead
Group content by topic, link within each group generously, and allow cross-links when they help the reader. That is closer to a topic cluster, and it keeps the benefits people want from silos without the stranded pages. The silos vs topic clusters guide weighs both approaches for real sites.