AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
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.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.