In more detail
Search engines discover most pages by following links. Google's SEO starter guide and its guide to crawlable links recommend making sure pages are linked from other relevant pages, using standard HTML links with descriptive anchor text.
Internal links do three things:
- Discovery. Pages with no internal links pointing to them ("orphan pages") may be found late or not at all.
- Context. Links and their anchor text tell search engines what the target page is about and how it relates to the linking page.
- Priority. Pages that receive many internal links, especially from strong pages such as the home page, tend to be treated as more important.
Navigation menus, breadcrumbs, related-content blocks and links within body text all count. Links in body text are often the most useful, because they sit in a relevant context.
Common problems include important pages buried several clicks deep, links that only work with JavaScript, many links pointing to redirected URLs, and generic anchors such as "read more" everywhere.
Why it matters when hiring an agency
Internal linking is one of the few SEO levers entirely under your control, and improvements can be made without waiting for other sites to link to you. A good agency will map which pages matter most and make sure they're well linked, especially pages that are close to ranking.
Ask how they'll find orphan pages and pages that sit too deep. When they recommend content, ask how new pages will connect to existing ones. Building clusters of linked pages around a topic is a core part of topical authority. Our Page Authority Checker shows how strong a page is, which helps decide where links should come from.