Cyberspace was, as the Eighth Doctor, explained, "A world within a world, a reality where nothing exists but lines of code, manipulating the fabric of the place in infinite ways." In this world, words were power. (PROSE: Lonely)
The Library's command node, CAL, contained cyberspace. Miss Evangelista revealed that repeating the same patterns over and over saved cyberspace. Donna Noble lived a false life here with a real husband but computer program children.
Eugene Jones believed that the alien who'd left behind the Dogon sixth eye he'd acquired contacted him through eBay to buy it, and was only able to speak to him through the website because it was cyberspace. (TV: Random Shoes)