Software

Here is a list of organizations and software projects that can result infrastructure as powerful and valuable as that owned by any large search engine or social networking site.

Free Software Foundation
Linux Kernel
Syslinux
Busybox
Document Foundation
Kernel Virtual Machine
Open Secure Shell (SSH)
Modules
TTY Linux

Noteworthy applications include:

LibreOffice
Maria DB
MediaWiki
WordPress

FUSE

Filesystem in Userspace (or FUSE) is one of the most useful technologies out there. Simply, it makes a server via a protocol appear as local data. Below is a list of favorite FUSE implementations.
SSHFS – Probably the most powerful of them all.
EncFS – Useful for per file encryption.

Resources

Wikpedia – http://en.wikipedia.org/wiki/Filesystem_in_Userspace

Low Level Importance

Intel CPU Microcode – Don’t leave home without it.

For those who have worked tirelessly on these projects, THANK YOU!