An IoT search engine crawls the internet the way a normal search engine crawls web pages, but instead of indexing content it indexes devices: servers, webcams, routers, industrial controllers, databases, and anything else with an open port. It records the service banners those systems return, so you can search for a specific software version, an exposed database, or every device of a given type in a given country.
For OSINT and security research this maps an organisation's external attack surface without ever touching it directly — the engine has already done the scanning. It surfaces forgotten servers, misconfigured storage, and exposed cameras, which makes it invaluable for defenders auditing their own exposure and for investigators footprinting a target's infrastructure.