When it first came out - and i’d say much less restricted for community use - it was a step change in my understanding of the extent of observability in place on the internet. I knew the NSA “was out there”, but never knew one could browse, StumbleUpon-style, random internet services and knock on their doors. At the time I dealt with a lot of smaller internet-facing applications, and was excited about being able to search for public instances of them and worried about others finding mine.

Shodan is the villain from System Shock: https://shodan.fandom.com/wiki/SHODAN

> SHODAN watches from Security Cameras, stares out of screens and monitors, sends threats and snide messages over the Station's PA system or via email to the player's data reader, and sometimes cuts off communications from friendly sources.

Shodan is first degree in Japanese martial arts or the go board game. Other stuff too like tea ceremony or calligraphy.

"Search Engine for the Internet of Everything"