Keyword cannibalisation happens when two or more pages on the same website target the same keyword, causing them to compete with each other in search results and split the ranking signals that should have backed a single strong page.
It quietly weakens your own site. Instead of one strong page ranking well, you get two mediocre pages, because the links, content signals and authority that should have concentrated on one page are spread across both.
It confuses search engines. When Google cannot tell which of your pages should rank for a search, it may rank the wrong one, or keep swapping, none of which helps you.
It is common and invisible. A business adds a new service page, a blog post and a location page over the years, all drifting onto the same keyword, and no one notices the pages are now fighting each other.
An accountant has a services page, a blog post and an old landing page all targeting tax return accountant. None of them ranks well, and Google keeps showing a different one each week.
The fix is to pick the page that should own that search, make it the strongest, and either merge the others into it or repoint them at clearly different keywords.
With the signals concentrated on one definitive page, that page can finally rank where three competing weak pages never could.
In-House detects cannibalisation through the SEO agent, identifies which page should own each keyword, and consolidates or re-targets the rest, with structural changes routed to you.