Google SEO
2009 — The 215 Guys
What does rel=canonical do for duplicate content?
Introduced jointly by Google, Yahoo and Bing, rel=canonical identifies the preferred version of duplicate content and helps consolidate authority around one URL instead of spreading it across several.
Further analysis
Use this entry as an audit checkpoint. The cited source establishes the context; the direct answer identifies what to check before choosing an action.
In SFT, this topic relates to Structure. Check whether the signal is visible on the page, connected to the rest of the website and supported by understandable evidence.
Related search terms include canonical, duplicate content, 2009. Use them to describe the issue in a brief, audit or answer page.
Applying SFT
Structure turns a rule into readable architecture: headings, URLs, structured data, visible content and clear hierarchy.