Google is a search engine for human readable content. Shodan does the same for machine readable content.
You can:
search for specific IP addresses, and it will show you the active ports, and running services.
search for a specific response header in the set of countries
browse through the screenshots of open VNC & RDP
open webcams
and more...
The free accounts can use any feature, but the list of results is limited.
But if you really want to look under the deck of the internet, the subscription is worth it.
Well, if you buy a cheap insecure camera, and point it to a giant satellite dish in some kind of space observatory, you can't be surprised that people will want to have a look. At that point, you're basically asking for it. /s
Yeah... that was a good find. I sent the link to a friend immediately, and we were yelling like children "it's turning, it's turning!" every time it was repositioned.
That's cool AF. Shodan shows lots of cool things that I don't think anybody minds being seen, but it also gives search results that could be used nefariously. It's probably the coolest and creepiest tech product I've ever seen.
Well, if you ever asked yourself "How can I nmap the whole internet without wasting months of my life?" Shodan is for you. Otherwise, it's probably not.
If you're still curious anyway, I'm not the best person to pitch it to you... but I know just the right guy - Viss, and his DefCon presentation. Shodan is a tool that can help you find stuff that he talks about.
I believe it was the fictional artificial intelligence that became self-aware and tried to take over the world in the game System Shock, and later System Shock 2.