<https://cleardoorseo.com/4-pillars-of-seo/>
<http://schema.org/description>
"The 4 pillars of SEO are 1) Technical SEO 2) Content writing 3) On-page SEO 4) Off-page SEO. These SEO pillars will help build a strong website foundation."
<https://cleardoorseo.com/4-pillars-of-seo/>