The rel=canonical link tag should only appear in the
of an HTML document. Additionally, to avoid HTML parsing issues, it’s good to include the rel=canonical as early as possible in the
. When we encounter a rel=canonical designation in the
, it’s disregarded.
This is an easy mistake to correct. Simply double-check that your rel=canonical links are always in the
of your page, and as early as possible if you can.
rel=canonical designations in the
are processed, not the
.
Conclusion
To create valuable rel=canonical designations:
Verify that most of the main text content of a duplicate page also appears in the canonical page.
Check that rel=canonical is only specified once (if at all) and in the
of the page.
Check that rel=canonical points to an existent URL with good content (i.e., not a 404, or worse, a soft 404).
Avoid specifying rel=canonical from landing or category pages to featured articles as that will make the featured article the preferred URL in search results.
And, as always, please ask any questions in our Webmaster Help forum.
Written by Allan Scott, Software Engineer, Indexing Team