"A consensual hallucination experienced daily by billions of legitimate operators, in every nation, by children being taught mathematical concepts. … A graphic representation of data abstracted from banks of every computer in the human system. Unthinkable complexity. Lines of light ranged in the nonspace(sic) of the mind, clusters and constellations of data. Like city lights, receding."
The word cyberspace was coined by William Gibson in the novelette Burning Chrome, but was more notably popularized by the above quote from page 69 of his latter publication, Neuromancer in 1984.
Being disoriented and lost in a string of random meaningless links on the internet which finally ends on a topic completely different to what you originally had in mind.
Person 1: Dude, what happened? You've been in front of the computer for an hour but didn't even start your work.
Person 2: I know, I guess I was just completely cyberspaced out.
Any web site where, upon entry, hours of time collapse, sucked into infinity as you struggle to break free from the mesmerizing yet senseless, non-productive locale. Often seemingly innocuous on the outside and discovered quite by accident, Cyberspace Black Holes are known to cause unaccountable absences from work, school and important events, and should be considered particularly dangerous for the time-constrained and those who wish to keep their jobs.
After Billy had missed a week of work and no one had heard from him, police broke down his door fearing foul play only to find him sitting at his computer, dehydrated and malnourished but alive, laughing hysterically as he scrolled page after page of the CyberspaceBlack Hole he had entered eight days earlier.
A rapid number of new webpages are created and old articles are being replaced with new ones. Therefore if one wishes to look up one if these old websites or articles, it becomes increasingly difficult with time to find it. Whether it simply doesn't show up on google or was replaced by a more recent webpage we say it got "lost in cyberspace" and may as well have burnt in the Cyber version of the Library of Alexandria.