Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Jekyll is a blog-aware, static site generator for personal, project, or organisation sites.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.