A canonical tag (rel="canonical") is an HTML element that helps prevent duplicate content issues by specifying the "canonical" or "preferred" version of a web page.

Why It Matters:

• Prevents duplicate content penalties
• Consolidates link equity to preferred URL
• Helps search engines understand your preferred version
• Essential for e-commerce and content sites

Common Use Cases:

• HTTP vs HTTPS versions
• www vs non-www versions
• URL parameters (tracking, sorting, etc.)
• Printer-friendly or mobile versions