Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Mailchimp is a marketing automation platform and email marketing service.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Snipcart is a shopping cart platform that can be integrated into any website with simple HTML and JavaScript.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.
Yoast SEO is a search engine optimisation plugin for WordPress and other platforms.