Definition
A noindex directive tells search engines not to include a page in their results. It's set with a meta robots tag in the page or an X-Robots-Tag HTTP header:
<meta name="robots" content="noindex">When to use it
- Thank-you and confirmation pages.
- Internal search results and filtered listings.
- Staging copies and duplicates.
Common mistake
Blocking the page in robots.txt as well. A crawler that can't fetch the page never sees the noindex, and the URL may still appear in results without a description. Let the page be fetched and use noindex.