OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
Vimeo is a video hosting, sharing and services platform. Vimeo operation an ad-free basis by providing subscription plans.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.