Making a page noindex is a way to ask search engine spiders to not index a particular web page. If a page is not indexed by a search engine it cannot show up in their search results.
This is what the HTML code for noindex looks like:
<meta name="robots" content="noindex" />
If a web page does not have valuable content, it can be a good idea to noindex it. But you want to make sure not to accidentally noindex pages that you care about and would like to show up in search results.
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