Child canonicals can have a significant impact on SEO. Here are some key points to consider:

• Google's Compliance: Even though a canonical tag is meant to indicate the preferred URL to Google, the search engine might not always adhere to this directive.
• Canonical Selection: Both internal and external signals might influence Google to select a child URL as the canonical over the intended parent URL.
• Cannibalization: Child canonicals can lead to cannibalization, where they compete with parent pages for ranking, diluting the effectiveness of both.
• Indexing Issues: If Google disregards the canonical tags, it might index both child and parent URLs, which can spread link equity thin and weaken the ranking potential of important pages.

In essence, child canonicals can disrupt the clear hierarchy and authority of pages, leading to a less efficient and potentially problematic index.

To avoid canonicalization issues with Shopify's default SEO configuration, it's essential to take control of how your website's URLs are structured. Shopify's out-of-the-box configuration might not be ideal, as it often sets product URLs as children of collection pages, which then canonicalize to the root product URL. This can be problematic if the content on the child page is different from the parent. To address this, you should:

• Customize URL Structures: Adjust the URL structures in Shopify to prevent unnecessary stacking of child canonical URLs.
• Review Canonical Tags: Regularly review and correct canonical tags to ensure they accurately reflect the desired hierarchy of your content.
• SEO Expertise: Consider consulting with an SEO expert who has experience with Shopify to optimize your site's canonical setup for a healthier index.

Minimizing canonicalization on a website is important because it helps maintain a healthier index in search engines. Canonical tags were originally created to address duplicate content issues by telling search engines which version of a similar page is the preferred one. However, when used excessively or incorrectly, canonicalization can lead to several problems:

• Duplicate Content: It can confuse search engines and lead to duplicate content issues if not handled properly.
• Link Equity: Incorrect canonicalization can dilute link equity by spreading it across multiple similar pages instead of concentrating it on a single authoritative page.
• Search Engine Rankings: It can negatively affect search engine rankings due to cannibalization and mixed signals sent to search engines.

Therefore, it's crucial to control canonicalization and ensure that canonical tags are used correctly to signal the relationship between documents without causing confusion or inefficiencies.