Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Gravatar is a service for providing globally unique avatars.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
MonsterInsights is the most popular Google Analytics plugin for WordPress.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
Varnish is a reverse caching proxy.
WooCommerce is an open-source ecommerce plugin for WordPress.
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.