AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
cdnjs is a free distributed JS library delivery service.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
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.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
RackCache is a quick drop-in component to enable HTTP caching for Rack-based applications.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.