The internet primarily runs on open source software. Your browser is primarily open source software, unless it's IE/Edge, but let's be serious here. Your phone - primarily open source, unless it's WP/BB, but again, let's be serious.

The desktop/laptop you're using right now probably isn't open source, but much of the important software running on it is, and most of the computers it talks to are, and most of the other computers, obvious or hidden, in your life are too.